The senior guard had five 3-pointers and made all 10 of his free throws to lead the Cougars (14-13, 6-9 Pac-10) to just their second win in Los Angeles in 53 tries.
"It was very exciting, for all of us," Rochestie said. "We've lost a couple of really close games and our coaching staff has been hanging with us.
"Today, to finally get over the hump, against a team like this, in an arena like this It meant a lot to me. It meant a lot to the team. It meant a lot to the seniors."
Rochestie scored 14 of Washington State's final 16 points, including a remarkable one-handed tip-in of his own miss and two 3-pointers.
"He's a fifth-year senior that nobody wanted," UCLA coach Ben Howland said. "He's a great story. I got a lot of respect for that kid. He's a great competitor. He willed them today, especially in the first half. He's a great player and I'll be voting for him, obviously, for all-league."
It was coach Tony Bennett's first win over UCLA in six tries and the Cougars' first win at Pauley Pavilion since beating UCLA, 55-48, on Feb. 5, 2005. UCLA leads the all-time series 94-14.
"This feels great because we've been close against UCLA so many times and been close this year in games so many times," Bennett said. "We matched them in scoring. I wish we'd score like that all the time. That would be fun."
Freshman Klay Thompson scored 15 points, all in the first half, and added five rebounds and five assists for Washington State. Senior center Aron Baynes finished with 13 points, six rebounds and four assists, while Caleb Forrest added 12 points on 6-of-8 shooting.
Forward Nikola Dragovic scored a career-high 23 points, including five 3-pointers, for the Bruins (20-7, 9-5). Darren Collison had 20 points and eight assists, while Josh Shipp scored 14 points and Alfred Aboya had 13 points and 11 rebounds.
UCLA scrambled late, forcing loose ball situations and a few turnovers. Collison made a 3-pointer with 1:26 left to cut the lead to 75-71, but couldn't capitalize on two steals by Dragovic, missing a layup and 3-pointer on consecutive possessions. Thompson sealed the upset when he blocked a buzzer-beating attempt by Shipp near halfcourt after Nikola Koprivica missed two free throws with 2.1 seconds remaining in the game.
"It was a frantic finish," Bennett said. "Some of the turnovers, going both ways and some of the shots being made, it was just hold on and whoever is standing wins."
Washington State shot 58.8 percent from the field for the game hitting 12 of its first 16 shots and eight of 15 free throws. Thompson got the Cougars started, making his first five shots, including three 3-pointers.
Trailing by seven with 3 minutes to play, UCLA looked ready to rally after Shipp scored on a layup and appeared ready to score again on a turnover. Instead, he passed on an open slam dunk and missed the layup. The Cougars turned the miss into a transition opportunity and Rochestie drained a 3-pointer to complete a five-point turnaround.
UCLA rallied from an eight-point deficit to force a 42-42 halftime tie and then built a 51-46 lead over the first 4 minutes of the second half.
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