LOS ANGELES -- Arizona spent a lost weekend in Los Angeles two weeks ago, getting swept instead of clinching the Pac-10 regular-season title the first chance it had.
The Wildcats' latest visit is going much better.
Derrick Williams scored 20 points and Arizona (No. 15 ESPN/USA Today, No. 16 AP) held off Southern California 67-62 Friday night to earn a spot in the Pac-10 tournament title game for the first time since 2005.
"We played better. We handled it better," Wildcats coach Sean Miller said. "I thought part of what's helped us here this weekend is we came here trying to be better than we were a couple weeks ago, and our team is more together and has a better mindset. If there was a total team win we had this season, tonight was the night."
The top-seeded Wildcats (27-6) have won 12 of 14 games entering Saturday's championship, a trophy they last won in 2002.
"As long as we get the win, I'm happy," said Williams, who is from nearby La Mirada.
Jesse Perry added 11 points for Arizona, which had its 25-year NCAA tournament streak end last year when the Wildcats stayed home. But as the Pac-10's highest-ranked team this season, they're headed back under league coach of the year Miller regardless of how they fare Saturday.
"I thought this was our best win of the season," Miller said.
Marcus Simmons, the Pac-10's defensive player of the year, led the Trojans with a career-high 20 points.
"I know I'm a defensive player. They were leaving me open. I wasn't uncomfortable shooting," Simmons said.
Nikola Vucevic scored 12 of his 16 points in the second half and had 12 rebounds.
"If I could limit his catches, I'm going to limit his points, so that's what I tried to do," said Williams, who defended Vucevic most of the game. "He was frustrated and stuff like that, so I just tried to get in his head a little bit and just try to stop him from scoring. He still had a double-double. Great players are going to score and rebound, especially at his size."
The fourth-seeded Trojans (19-14) played without coach Kevin O'Neill, whose suspension for the rest of the tournament was announced by USC two hours before tipoff. He and his wife got into a verbal altercation with an Arizona booster on Thursday night at the team hotel.
Bob Cantu, the Trojans' associate head coach in his 10th year with the program, took over and paced the sideline, regularly checking laminated play cards.
"It was different," Vucevic said. "When K.O. is there, he yells a lot and we didn't hear a lot of yelling. We still did a good job."
Cantu found out three hours before the game that he'd be in charge.
"I ran two plays that we hadn't run before. I laughed and said, 'K.O. is saying, 'Why is he running that play right now?' ' " Cantu said. "I felt that if we ran something different, they wouldn't expect it. So we threw a couple extra things in there, and a couple worked and a couple didn't."
With a USC fan holding up a "Free K.O." sign, the Trojans came out strong, taking a six-point lead at the start. They fell behind for good late in the first half and played catch-up the entire second half.
"I thought we really fought and we played really, really hard and really defended," Cantu said. "Anybody out there that was watching this game can see that we can compete with just about any team in the country."
Vucevic hit a pair of free throws to draw the Trojans within three with 2:29 left. Jio Fontan's 3-pointer left them trailing 63-60 with 48 seconds to go.
The Wildcats passed the ball around to kill time before Williams drove the lane and got fouled by Vucevic. He made both and kept Arizona ahead 65-60 with 20 seconds left.
Williams got fouled and made both before Fontan's jumper missed at the buzzer.
The Trojans fell to 0-4 all-time against Arizona in the Pac-10 tourney after the teams split during the regular season.
USC sat out last season's league tourney as part of self-imposed sanctions for NCAA violations involving former star O.J. Mayo, which made for a trying time during O'Neill's first season. The Trojans won 16 games after three players left early to play professionally and most of the recruiting class departed before the season began.
Neither team led by more than six points in the first half, when the Trojans shot 54 percent. Tied at 25, the Wildcats outscored USC 8-3 to take a 33-28 lead at the break. Vucevic missed an open 3-point attempt, one of just three shots he took, and Kevin Parrom grabbed the defensive rebound, feeding Williams for a fastbreak dunk that ended the half.
Arizona fans tweaked O'Neill's absence with one sign reading, "O'Neill leave our fans alone," while another read, "Hotel bar" with a black arrow pointing in one direction.