LOUISVILLE, Ky. — The losses came in rapid succession, leaving the men’s tournament with no more No. 1 seeds.

Alabama, seemingly on a roll with a conference title and a pair of comfortable N.C.A.A. wins, crumpled to San Diego State, 71-64. Minutes later, the tournament lost its final No. 1 when Houston, which was trying to reach the Final Four in its home city, lost to Miami.

It was the first time under the tournament’s current format that no teams seeded No. 1 had reached the round of 8, after Purdue and Kansas, last year’s champion, exited in the first weekend.

Alabama headed to the round of 16 with two other big threats in its region eliminated — second-seeded Arizona and third-seeded Baylor.

But on Friday night, the Crimson Tide found themselves bothered by San Diego State’s physical play and slow pace, and wasted a 9-point lead in the second half. Alabama’s star freshman, forward Brandon Miller, couldn’t rescue his team as he had regularly done this season, finishing with 9 points on 3-of-19 shooting and six turnovers.

Miller missed nine of 10 3-pointers — including one with 37 seconds left and Alabama trailing, 68-64. After a San Diego State free throw, Nathan Mensah blocked Jahvon Quinerly’s layup attempt — Mensah’s fifth block of the game — to all but seal it.

The Aztecs were lifted by Darrion Trammell, a 5-foot-10 transfer from Seattle University who poured in 21 points, equaling a season high. — Billy Witz

KANSAS CITY, Mo. — Kelvin Sampson, the coach of the Houston men’s basketball team, has been surprisingly blunt this month about his team’s deficiencies. Never mind the Cougars’ No. 1 seed, Sampson said this week. Never mind their 33-3 record. The season has often been a struggle, he said, and success in the men’s N.C.A.A. tournament was far from guaranteed.

Sampson’s words proved painfully prescient on Friday night, as Houston fell, 89-75, to Miami in a unexpectedly one-sided round-of-16 matchup in Kansas City.

Miami, a No. 5 seed, played crisply and confidently as underdogs, benefiting from a scintillating shooting performance from the star point guard Nijel Pack, who finished the game with 26 points.

With the win, the Hurricanes, who shot 51.7 percent from the field as a team, advanced to the regional finals for the second straight year. They were blown out in that round last year by Kansas, the eventual national champions.

Miami looked sharp from the tipoff, going up 42-36 after a hard-fought first half that featured seven lead changes. Pack and shooting guard Isaiah Wong (20 points) kept poking holes in the vaunted Houston defense, slashing their way into space, wriggling free for open looks along the 3-point line.

Pack, in particular, bounced through the game in a seemingly unshakable groove. The point guard, who transferred to Miami last year after two seasons with Kansas State, shot 8 of 12 from the field, including 7 of 10 from 3-point range.

“We’re just happy to have him,” Miami Coach Jim Larrañaga said before the game about Pack. “He’s a fantastic shooter, but he’s also working very hard defensively, and he’s sharing the ball with his teammates as the quarterback of our team.”

Miami scored 5 quick points after the break, forcing Sampson to take a timeout, and essentially never looked back, stretching its lead with relative ease. Houston shot just 37.5 percent from the field, the players’ droopy body language reflecting their night of struggles.

With the loss, the Cougars’ dream of participating in the Final Four in their home city came to a sudden end. Sampson had been asked this week how meaningful, how exciting, such a turn of events would be. He refused to entertain the notion. He knew too well how precarious, and how fleeting, success could be. — Andrew Keh

SEATTLE — In the first few minutes of the women’s round-of-16 matchup between Iowa and Colorado, it would have been easy to think the game was being played at Carver-Hawkeye Arena in Iowa City. The Hawkeyes led early, and a crowd of fans in yellow-and-black jerseys erupted after each shot.

They had reason to feel at home, as second-seeded Iowa outlasted the Buffaloes, 87-77, to earn a spot in the round of 8. The Hawkeyes will face Louisville on Sunday.

But it was not an easy win.

Colorado kept things close early, and in the second quarter, the Buffaloes appeared to be taking control. Their aggressive play held Iowa in check, and Frida Formann’s 19 first-half points helped Colorado go into halftime with a 1-point lead, 40-39.

Yet the question from the beginning seemed to be how much Colorado could slow down Caitlin Clark, one of college basketball’s most feared stars because of her shooting. Not quite enough, it turned out.

Clark scored 13 points in the first half and finished with 31. She had 11 in the third quarter alone as Iowa took the lead quickly then built it up.

When Clark stole the ball and flew across the hardwood for a layup to cap a 13-point run, the crowd erupted as if she had secured the win.

Effectively, she had. — Talya Minsberg

LOUISVILLE, Ky. — Princeton’s Matt Allocco, a determined junior guard, stuck with Creighton’s sinewy Arthur Kaluma as he drove into the lane. Allocco cut off Kaluma’s path to the basket, stayed with him on a pivot and got a hand up as Kaluma lofted a fadeaway jumper that nestled through the net.

As it did, Allocco shook his head.

It was far from resignation, but it was a sign that Princeton, which surged into the second weekend of the men’s N.C.A.A. tournament with inspired team basketball that belied its status as a No. 15 seed, knew what it was up against on Friday night in Louisville.

Creighton, with its scintillating ball movement, sharp shooting and heady play, is what an Ivy League team might look like with a roster dotted with players who will continue their careers as professionals.

The Bluejays, who navigate the rough and tumble Big East, eased their way into the South Regional final on Sunday against San Diego State by pulling away from Princeton for an 86-75 victory.

The game will be a rematch of last year’s first-round game won by Creighton in overtime. It will also be a family affair: Creighton’s Kaluma is the younger brother of San Diego State guard Adam Seiko, whose 3-pointer put the Aztecs ahead to stay in their upset of top-ranked Alabama.

Both teams will be aiming for their first appearance in the Final Four, and it will be a contrast of styles — San Diego State’s grinding defense putting the Creighton offense to the test.

Creighton’s offense flowed to full effect on Friday. The Bluejays worked center Ryan Kalkbrenner on the interior, with the 7-foot-1 junior scoring 22 points on 9-of-12 shooting. And Baylor Scheierman, a headband-wearing sharpshooter, led the perimeter game with 21 points on 8-of-11 shooting, including five 3-pointers.

Princeton, which trailed by 16 points in the second half, somewhat stymied the Bluejays for a stretch with a 1-3-1 zone. The Tigers closed to 76-69 with 3:38 left, but Kalkbrenner’s layup and dunk, sandwiched around a free throw by Kaluma, kept Princeton at bay. — Billy Witz

SEATTLE — Mississippi came swinging into its game in the round of 16 of the women’s N.C.A.A. tournament, less than a week after upsetting No. 1-seeded Stanford.

The eighth-seeded Rebels took an early lead in the first quarter, but it didn’t last. Despite a strong defensive game, Mississippi was unable to hold off No. 5 seed Louisville, which won, 72-62, to move on to the round of 8.

Though both teams played aggressively and with a sense of urgency, Louisville closed the first half with a 7-point run that proved to be the start of the Cardinals’ pulling away. Mykasa Robinson hit a jumper at the start of the fourth quarter to push the lead to 12, and the Rebels posed little threat from there.

In the final seconds, Hailey Van Lith dribbled the ball in place to run out the clock. The native of Wenatchee, Wash., had scored 21 points in her home state, and her team was headed to the next round. “Oh my God,” she mouthed toward her teammates.

The Cardinals will face No. 2 seed Iowa in the round-of-8 game on Sunday. — Talya Minsberg

GREENVILLE, S.C. — The round-of-16 game was slipping away from Miami, as Villanova closed a 21-point gap.

But the ninth-seeded Hurricanes stopped the reversal in the final minute, scoring 6 straight points to beat fourth-seeded Villanova on Friday, 70-65, to advance to its first round-of-8 game in the women’s N.C.A.A. tournament.

“I can’t believe it,” Miami Coach Katie Meier said. “I’m not going to act cool. This is awesome.”

Villanova had cruised to the round of 16, beating its lower-seeded opponents by an average of 18 points. The Wildcats seemed to be building for a run behind their star, Maddy Siegrist, the top scorer in Division I.

But from the beginning of Friday’s game, it was clear that this matchup would be much different from Villanova’s earlier games.

Miami’s defense smothered Villanova’s ballhandlers, hounding them as soon as they inbounded the ball. Miami’s speed and physicality made up for a height disadvantage and forced rushed shots and turnovers, causing Villanova’s offense to look confused. By the time Villanova seemed to have figured out Miami’s defense in the second half, it appeared to be too late.

But Siegrist, who scored a game-high 31 points, led a furious rally in the third and fourth quarters as Miami tightened up, seemingly fearful of spiraling. Still, the Hurricanes held close even though they blew their lead.

Siegrist, who could leave college early to declare for the W.N.B.A. draft, tearfully said after the game that her future was uncertain.

“I’ve got to talk to my parents and stuff,” Siegrist said. “But I couldn’t be more grateful for the opportunity to be here. Like so many good people, and it’s really about the people, take the basketball part out of it, the memories and people I will cherish forever.”

Miami had faced a much more difficult path to the round of 16 than Villanova, with close games and a win over Indiana, a No. 1 seed, on its home floor.

Miami will play Louisiana State on Sunday. — Kris Rhim

GREENVILLE, S.C. — Louisiana State’s star forward Angel Reese headed toward the sideline with her face in her palms after fouling out with just over four seconds left, her team holding a 1-point lead. Utah forward Jenna Johnson went to the free-throw line, the L.S.U.-leaning crowd chanted loudly, and she missed both.

No. 3-seeded L.S.U. got two more free throws and a critical final stop to eke past No. 2 seed Utah, 66-63, to advance to the round of 8 for the first time since 2008.

Utah seemed focused on taking away Reese, and the Utes did slow her down a bit, holding her to 17 points.

But that strategy freed up opportunities for forward LaDazhia Williams, who scored 24 on 11-of-14 shooting, often celebrating when her buckets went in.

“They’re not a one-trick pony, as they say,” Utah Coach Lynne Roberts said. “They got a lot of good players.”

Williams scored 7 points in the second quarter, after Reese picked up her second foul and left the game. Utah had looked like it might be pulling away, but Williams kept L.S.U. close. “I felt like I needed to step up as a senior,” said Williams, who called the game the best of her career.

L.S.U. had been a regular contender in the early 2000s, making five straight Final Fours. But the program had seen a decline until Kim Mulkey arrived from Baylor ahead of last season. Mulkey, a three-time national champion, added transfers, like Reese, and immediately made the Tigers relevant again.

Mulkey has worried that their fast start might create outsize expectations in Baton Rouge. “Might be feeding that monster too quickly, but it sure beats the heck out of losing,” she said.

L.S.U. will play Miami on Sunday. — Kris Rhim

KANSAS CITY, Mo. — Suddenly the top-seeded team in the men’s N.C.A.A. tournament, Texas is ever closer to a home-state advantage at the Final Four.

The Longhorns on Friday easily discarded third-seeded Xavier, which looked sluggish and disorganized working against its opponent’s noisy defense and fast-moving offense.

The last No. 2 seed left in the tournament, Texas led the entire game en route to an 83-71 victory in its first round-of-16 appearance since 2008. The win was the Longhorns’ fourth this month in T-Mobile Center, where they also were crowned the Big 12 Conference tournament champions.

Texas started four transfers, underscoring the transience of modern college basketball and the rewards for coaches willing to adjust to annual roster turnover.

There was Marcus Carr, formerly of Minnesota and Pittsburgh, who led the team’s fast-paced offense with 18 points and 6 assists. Timmy Allen, an athletic wing player who once starred at Utah, scored 11 points. And Tyrese Hunter, a former Iowa State guard, led the team with 19 points. The team’s leading scorer in its first two tournament games, Dylan Disu, formerly of Vanderbilt, started the game but left with a foot injury and returned to the bench in a conspicuous walking boot.

Xavier was led by the rangy 7-foot graduate student Jack Nunge — a transfer himself — who had 15 points and 11 rebounds.

The Musketeers appeared unprepared for Texas’s speed. Early in the second half, Xavier players had their hands on their hips, panting while trying to keep up with the Texas guards.

There was provincial pride in the Texas victory in Kansas City. Earlier Friday, on the same court, the school’s higher-ranked neighbor, Houston, crashed out of the tournament as the lone remaining No. 1 seed.

That loss left the Longhorns as the last remaining Texas team in a tournament that had been stacked with them. The school is working to reclaim the top position in the state’s amateur basketball hierarchy after two in-state rivals, Houston and Baylor, have surged in recent years. — Noah Weiland