No. 1 Notre Dame loses Brianna Turner to a knee injury but finds a way to get the win in overtime over No. 9 Purdue 88-82. (0:52)

The two No. 1 seeds in action Sunday in the women's NCAA tournament were both pushed to the limit but advanced to the Sweet 16. However, it potentially came at a big cost for both as Notre Dame and South Carolina might have lost key players to injury.

The top-seeded Fighting Irish beat No. 9 seed Purdue 88-82 in South Bend, Indiana, and advance to the regional semifinals for the eighth season in a row. Notre Dame will face No. 5 seed Ohio State in the Lexington Regional on Friday.

But in the final minute of the second quarter, Irish junior forward Brianna Turner's knee appeared to buckle under the basket. She left the court and did not return to the game. Turner had 10 points on 5-of-7 shooting from the field before she was hurt. She entered the game as the Irish's leading scorer (15.5 PPG) and rebounder (7.2 RPG) this season.

Earlier in the evening, No. 1 seed South Carolina held off No. 8 Arizona State 71-68 behind a double-double from A'ja Wilson (21 points, 11 rebounds) and 20 points from Kaela Davis. However, late in the game, South Carolina lost junior guard Allisha Gray, who fell hard to the floor on her knee. She did not return to the game, leaving with 11 points and eight rebounds.

South Carolina, which is in the regional semifinals for the fourth year in a row, was already down a starter. Before the tournament even tipped off, senior center Alaina Coates was ruled out because of an ankle injury.

In the Stockton Regional on Saturday, the Gamecocks will face the winner of Monday's second-round game between No. 4 seed Miami and No. 12 Quinnipiac.

Last year, both Notre Dame and South Carolina were also No. 1 seeds, and were upset on the same day in the Sweet 16 by No. 4 seeds. This season, they both won their conference regular-season and tournament titles again.

South Carolina did that in the SEC tournament with Coates playing just four minutes in the semifinal. The Irish won the ACC tournament with Turner healthy, and her absence in the second half Sunday clearly impacted Notre Dame.

Purdue, which tied for fourth in the Big Ten and then made the league tournament final before losing to Maryland, had a chance to win at the end of regulation against Notre Dame, but wasn't able to get off a shot. Then the Irish guards, who had to carry the load with Turner out, really came up big in overtime, scoring all 14 of Notre Dame's points.

Notre Dame is not a deep team in the post, even with Turner. If her injury keeps her out of the regional semifinal, the Irish's top guards -- Lindsay Allen, Arike Ogunbowale, Marina Mabrey and Jackie Young -- will have to lead the way again.

Notre Dame All-American Brianna Turner went down because of an apparent left knee injury in the final minute of the first half. AP Photo/Robert Franklin

If Gray is out for South Carolina, it takes away one of the team's most versatile and experienced players. Even though she's in her first season with the Gamecocks, Gray played in the Elite Eight as a freshman and to the Sweet 16 as a sophomore while with North Carolina.

A No. 1 seed had not lost in the second round of the women's tournament since Duke fell to Michigan State in 2009. Notre Dame and South Carolina avoided that fate, but both got to play on their home courts for the first two rounds. They won't have that advantage in their regionals.

There won't be a home team in the Lexington Regional because No. 4 seed Kentucky fell 82-68 to the Buckeyes in Sunday's first game. So far, the Wildcats are the only team to lose on its home court in this tournament, although eight more will be playing at home Monday. That includes No. 1 seed UConn, which faces No. 8 Syracuse (ESPN2/WatchESPN, 6:35 p.m. ET), the team the Huskies beat in the national championship game last season.

Two double-digit seeds still have a chance Monday to advance to the Sweet 16: No. 12 Quinnipiac, which plays at No. 4 Miami (ESPN2/WatchESPN, 9:10 p.m. ET), and No. 10 Oregon, which plays at No. 2 Duke (ESPN2/WatchESPN, 6:40 p.m. ET).

Also, No. 7 seed Kansas State will be playing on its home court (ESPN2/WatchESPN, 6:35 p.m. ET), since No. 2 seed Stanford was not able to host due to a conflict with the Pac-12 gymnastics championships at the Cardinal's facility.

South Carolina's Allisha Gray was carried off the court after she struggled to bear weight on her injured leg. AP Photo/Sean Rayford

Chalk still has mostly ruled the women's bracket thus far, but we've come very close to numerous bracket-busters, or at least bracket-shakers. It started Friday, as No. 13 Belmont had a chance to send its game with Kentucky into overtime, but wasn't able to sink a last 3-pointer.

Then No. 15 seed Long Beach State had two shots to beat No. 2 Oregon State, but fell 56-55. And No. 11 South Florida lost 66-64 on a buzzer beater to No. 6 Missouri.

Then in Saturday's first-round games, New Mexico State tried to do what Long Beach State had just missed doing Friday -- become the first No. 15 seed to win in the women's tournament. The Aggies led No. 2 seed Stanford for three quarters before the Cardinal's size advantage kicked in and helped them secure a 72-64 victory.

No. 13 Florida Gulf Coast didn't get calls on either end at the conclusion of its game with No. 4 Miami, and Hurricanes survived 62-60. Quinnipiac did knock off No. 5 Marquette on Saturday. But another No. 12 seed, Penn, let No. 5 Texas A&M escape a 21-point deficit and lost 63-61. It was the biggest fourth-quarter comeback in women's NCAA tournament history.

Sunday saw more of the "almost" upsets that have made this tournament interesting, if unsatisfying for those who want to see the underdogs prevail. Along with the near-misses by Arizona State against South Carolina and Purdue against Notre Dame, No. 6 NC State also came close to joining the fun, but fell 84-80 at No. 3 Texas.

Purdue's Ashley Morrissette (23 points, nine assists) and Bridget Perry (22 points, nine rebounds), NC State's Miah Spencer (31 points) and Dominique Wilson (27 points), and Arizona State's Sophie Brunner (20 points, nine rebounds) were all seniors who played great but were eliminated by heart-breaking losses in their final games.

There were some mostly drama-free games on Sunday, too: No. 2 seed Mississippi State, No. 2 Oregon State, No. 3 Maryland and No. 3 Florida State all won by double digits and advanced to the Sweet 16.

Ultimately, though, the biggest stories on Sunday were knee injuries -- those of Notre Dame's Turner and South Carolina's Gray -- and how that might impact the rest of the tournament.