Derrick Williams scored 20 points and No. 16 Arizona 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.
The top-seeded Wildcats (27-6) have won 12 of 14 games and will play No. 3 seed Washington in Saturday's championship, a trophy they last won in 2002.
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 Sean Miller regardless of how they fare Saturday.
Marcus Simmons, the Pac-10's defensive player of the year, led the Trojans with a career-high 20 points. Nikola Vucevic scored 12 of his 16 points in the second half and had 12 rebounds.
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, took over and paced the sideline, regularly checking laminated play cards.
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.
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.
Donte Smith missed a 3-point attempt in front of USC's bench, but Maurice Jones got the rebound and Vucevic scored underneath, leaving the Trojans trailing by three with 4 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.