Derrick Williams scored 20 points and Arizona shot 61 percent in an 82-73 victory over visiting Southern California on Saturday.

Lamont Jones had 17 points for Arizona (18-4, 7-2 Pac-10), which was 30 of 49 from the floor and hit 10 3-pointers en route to its sixth win in seven games.

The Wildcats led 40-31 at the half and promptly broke open the game with a 12-4 run. Williams, who was 6 of 6 from the floor, scored seven points during the spurt, which gave Arizona a 52-35 advantage less than four minutes in.

Still looking for a signature win to boost its NCAA Tournament hopes, USC (12-10, 4-5) trailed by as many as 20 before a rally in the final two minutes fell short.

Nikola Vucevic led the way for USC with 20 points.

In the first half, the Wildcats broke open a two-point game with a 15-5 run, which gave them a 33-21 lead with 5:13 remaining. Kevin Parrom scored six points in that span. Jones’ free throw with 58 seconds left gave Arizona a 40-31 lead heading into the locker room.