Los Angeles ? Darren Collison scored 17 points and No. 2 UCLA capitalized on a late-game technical foul to beat 19th-ranked Southern California 70-65 Wednesday night.

The Bruins (21-2, 10-2 Pac-10) trailed until there was about six minutes left against the Trojans (18-7, 8-4).

With a victory, the Trojans could have tied UCLA for the conference lead, but instead they dropped to third behind idle Washington State (8-3).

UCLA extended its Pauley Pavilion winning streak to 18 games as the Pac-10’s only undefeated team at home.

Arron Afflalo scored 13 of his 16 points in the second half, including two free throws that gave UCLA the lead for good with 41â2 minutes left. Luc Richard Mbah a Moute added 11 points and 10 rebounds.

Nick Young led USC with 20 points, Gabe Pruitt added 16, and Lodrick Stewart 13. It was Stewart’s technical foul for spiking the ball that led to the Trojans’ undoing against their crosstown rivals in front of a raucous crowd that included former UCLA coach John Wooden and Gov. Arnold Schwarzenegger.

USC led by seven points early in the second half before things got tight.

The Bruins got within one for the first time with an 8-2 run, including four in a row by Mbah a Moute, whose fastbreak layup came off his own steal.

The teams traded baskets before Afflalo hit a three-pointer from deep in the left corner – just his second field goal of the game – that tied it at 46 and ignited the crowd.

Defense led to UCLA’s first lead of the game. Alfred Aboya took the ball away from Pruitt and heaved a long pass to a streaking Afflalo, who dunked with abandon for a 50-48 lead with 5:51 remaining.

But Pruitt got fouled by Collison, who crouched in frustration, and made both for another tie at 50.

Trailing by two, Josh Shipp scored and got fouled by Young, who picked up his fourth. Before Shipp could step to the line, though, Stewart earned the technical. Afflalo made both of those for a 54-52 lead, then Shipp completed his three-point play.

Collison drove the lane for a one-handed layup that kept UCLA ahead 59-54. USC’s RouSean Cromwell committed an intentional foul as the Trojans’ frustration grew.

Dwight Lewis and Pruitt hit 3-pointers in the closing seconds, but UCLA proved steady at the foul line to preserve the win.

The Trojans came out aggressively to start the game, pulling away to a 20-10 lead while shooting 82 percent from the floor. They scored 11 points off UCLA’s nine turnovers in the half.

The Bruins struggled offensively, missing several open shots until they outscored USC 11-4 to end the half trailing 30-29.