Villanova began to resemble the Final Four contender many people expected it to be in the first half Tuesday night.
The Wildcats looked more like the team that had lost four straight in the second half.
Anthony Crater scored on a driving layup with 5.1 seconds remaining, and a last-ditch shot by Maalik Wayns at the buzzer clanked off the rim, allowing South Florida to stun the 10th-seeded Wildcats 70-69 in the Big East tournament.
Villanova squandered a 16-point lead by making only four field goals in the second half.
''I don't think any of us have ever finished a season this way,'' Villanova coach Jay Wright lamented afterward, ''so we've got to get their heads right.''
Wayns finished with 24 points for the Wildcats (21-11), who slipped from No. 6 in the nation earlier this season all the way to the first round of the Big East tournament. Now, assuming they're still selected, they'll slip into the NCAA tournament having lost five straight.
Their collapse was complete when Wayns threw away an inbound pass with 22.8 seconds left that Crater converted into a go-ahead layup.
The Wildcats' sophomore guard looked as though he might redeem himself when he was fouled on his own drive to the basket and made both free throws, but the 11.6 seconds left on the clock turned out to be too much.
Crater took the inbound pass and went the length of the floor, slipping by a confused Villanova defense for an easy layup - and the biggest win for South Florida in a while.
''The last play was designed for me to come off ball screen,'' Crater said, ''but I saw the lane was OK so I took it.''
Shaun Noriega made six 3-pointers and scored 22 points to lead the 15th-seeded Bulls (10-22), who had lost eight of their past nine coming into the tournament. Augustus Gilchrist added 16 points and Jawanza Poland had 11.
It was only the second Big East tournament win for the Bulls since joining the league for the 2005-06 season. They'll play No. 7 seed Cincinnati on Wednesday night.
''That was a great, great game,'' coach Stan Heath said. ''I'm really proud of our team's gutsy performance in the second half. In the first half, it didn't seem like we were guarding anybody. In the second half, we defended and got to loose balls.''
Just about the only bright spot for Villanova was the return of sharpshooter Corey Stokes, who was questionable with a left hamstring injury he sustained in practice March 3.
Stokes didn't start the game but checked in almost immediately, hitting a pair of quick 3s and appearing to move well. He had 16 points as the Wildcats closed the first half on a 28-7 run to build a seemingly insurmountable 49-33 lead - but he didn't score at all in the second half.
The Wildcats have certainly been a banged-up bunch this season, with leading scorer Corey Fisher - who had 15 points against South Florida - dealing with severe tendinitis in his right knee, and Wayns suffering from back spasms only a few weeks ago.
'Nova can add forward Mouphtaou Yarou to the list.
The big man went up to block a shot late in the first half and slammed hard to the floor under the South Florida basket. He didn't move for several minutes as Wright and a trainer checked on him, then helped him back to the locker room. He reappeared on the bench a couple minutes into the second half with stitches to his cheek and ice wrapped around his ribs.
''When it rains, it pours. I think that's what's happening. We've just got to fight through it,'' Wright said. ''We've got to keep our heads up.''
The Wildcats went the last 8 minutes of the game without a field goal, finishing 4 for 18 from the field in the second half, and yet nearly held off the feverish South Florida rally by converting 22 of 24 free throws.
The two misses were costly, though.
Wayns, an 81 percent foul shooter, clanked the front end of a 1-and-1 with 48 seconds left in the game. Then came Stokes, an 89 percent foul shooter, who also missed a front end 9 seconds later, giving South Florida plenty of hope.
''The way our season went, to get this win is so nice because it's been a long season,'' Noriega said. ''To get this win and upset Villanova, we feel really good about that.''
