CORVALLIS, Ore. (AP) - Oregon State gave Roberto Nelson two chances to beat USC - one at the end of regulation and another in overtime.
Nelson missed his opportunity to break a 72-72 tie in regulation, but he made no mistake on his off-balance layup in traffic with 25 seconds to play in overtime as the Beavers downed the Trojans 76-75 Thursday night.
Pe'Shon Howard had a chance to pull USC even after making the first of two free throws with 0.9 seconds left, but missed the second and Devon Collier grabbed the rebound for Oregon State.
"I can't believe we won that game," Beavers coach Craig Robinson said. "We have been on the other end of so many of those."
Angus Brandt finished with 14 points and Eric Moreland grabbed 10 rebounds and blocked four shots for the Beavers (12-8, 3-4 Pac-12), who trailed 39-36 at halftime.
Byron Wesley led USC (10-11, 1-7) with 23 points as the Trojans lost for the seventh time in eight games.
Tied at 74-74, the Beavers ran an isolation play for Nelson, who started near the top of the lane on the left side and then weaved his way through three defenders before laying the ball in off the glass.
"That one had a little bit of luck to do with it," said Nelson, who scored 14 of his 24 points after halftime. "It was a good thing my legs were still holding up, so I think I have to give that one to our strength coach, Jeff Macy."
At the other end, Wesley missed a layup attempt to tie for USC with eight seconds left and Daniel Gomis rebounded for OSU. Gomis passed ahead to Nelson, but Howard stole the ball for the Trojans and was fouled by Gomis driving to the basket.
Howard, a 73.1 percent free throw shooter, had made 7 of 7 from the foul line before his final attempt was strong off the back of the rim.
"It's a disappointing loss," said Trojans coach Andy Enfield, whose team made 19 of 21 free throws. "We played well. We played hard. To come down to the last play of the game and miss a free throw is tough."
Robinson's call for improved defense after Saturday's 87-81 loss at Washington didn't carry over to the start of Thursday's game as USC jumped out to 21-13 lead after the opening 9:40.
The Trojans maintained at least a two-point lead through the remainder of the first half as USC shot 50 percent (15 of 30).
After Eric Moreland grabbed an offensive rebound and scored to lift Oregon State into a 46-46 tie early in the second half, the Beavers came away empty on their next four possessions and the Trojans got a go-ahead 3-pointer from Nikola Jovanovic and a dunk from Omar Oraby to make it 51-46.
The Trojans led 61-55 with 8:31 remaining when Oraby fouled Brandt, giving him four personal fouls. Oraby then drew a technical foul for arguing the call, earning the 7-foot-2 senior center a fifth personal foul and a disqualification after he had scored 13 points with eight rebounds.
"They called him for a foul and he didn't open his mouth," Enfield said. "What I got was he stared at the official and he gave him a technical foul.
"He had to do a better job of controlling his emotions. He was playing great basketball and we needed him down the stretch."
Oregon State took a 68-67 lead on a Nelson 3-pointer, but Wesley hit two free throws to put the Trojans back in front and then connected from long range to make it 72-68 with 3:05 remaining.
Trailing 72-69, Gomis missed a dunk attempt in transition, but Hallice Cooke ended up with the loose ball behind the 3-point line and scored to pull the Beavers even with 52.2 seconds left.
The Beavers ended up with the final shot before the end of regulation, but Nelson's pull-up jumper from the left elbow was too strong.
"That's something one of the coaches and I practice every shoot-around and at the end of every practice," Nelson said. "It's one of those things where sometimes it goes in and sometimes it doesn't. I felt good going into it, but I can't shoot it over the rim like I did."
Collier had 13 points off the bench and Hallice scored all 11 of his points in the second half for the Beavers, who won despite shooting 41.9 percent (26 of 62) from the field and 57.1 percent (20 of 35) from the free-throw line.
"This game had nothing to with coaching," Robinson said. "This game had everything to do with the character of those guys in the locker room and their unwillingness to give up. They just kept grinding. It's an amazing win."
Howard had 16 points and Oraby was the only other USC player to score in double figures for the Trojans, who came away empty on five of their seven possessions in overtime.