LOS ANGELES — Juron Criner stumbled into the end zone with a 36-yard touchdown pass from Nick Foles with 3:14 to play, and Arizona wrapped up its best regular season in a decade Saturday with a 21-17 victory over not-so-mighty Southern California.

Foles passed for 239 yards and two TDs and ran for another score for the Wildcats (8-4, 6-3 Pac-10), who finally beat No. 20 USC for the first time in coach Mike Stoops' tenure by scoring the final touchdown in a defense-dominated game.

After Jordan Congdon made a 37-yard field goal with 7:13 left to put the Trojans (8-4, 5-4) ahead, Arizona converted three straight third downs on the decisive drive. Criner then caught a long fade pass and fought through a tackle into the end zone, silencing the nearly half-empty Coliseum crowd watching USC's second home loss in three games.

The Trojans were 47-1 at the Coliseum before last month's loss to Stanford, but their second home defeat finished off the most embarrassing season of coach Pete Carroll's remarkable tenure.

Arizona secured a share of second place in the Pac-10 with its first eight-win regular season since 1998 by knocking off a ranked team for the sixth straight season under Stoops, who has finally beaten every team in the conference.

Foles struggled in a 22-of-40 performance, but made several big throws — including an early TD pass to Delashaun Dean set up by an interception — while the Wildcats played again without leading rusher Nic Grigsby, who has a sprained shoulder.

Not even Senior Day could coax any consistency out of the dismal USC offense led by Matt Barkley, who went 20 of 37 for 144 yards with the 12th interception of his rocky freshman season. Allen Bradford rushed for 66 yards and a tying touchdown late in the third quarter, and Ronald Johnson caught a TD pass.

After beginning the season in search of their eighth straight Pac-10 title and BCS bowl berth, the Trojans are likely to finish in sixth place. A victory over Arizona likely would have put them in the Holiday Bowl, but now they could be headed for a more humbling trip to San Diego for the Poinsettia Bowl.

USC couldn't get a first down on its ensuing drive after Criner's catch, with Barkley throwing three straight incompletions — including a fourth-down throw over the head of Damian Williams, who was open down the middle. USC got the ball back with seven seconds left, but Barkley was sacked by Earl Mitchell.

Both teams already played their traditional season-ending rivalry games last week, with USC beating UCLA 28-7 and Arizona holding off Arizona State 20-17.

With USC wrapping up its least successful season since 2001, the Coliseum had tens of thousands of empty seats under appropriately cloudy skies. The Trojans were mostly lifeless early, trailing 14-7 at halftime and managing just 120 yards of offense in the first half.

Joe McKnight managed just 35 yards while playing with a bruised thigh, but still became the Trojans' first 1,000-yard rusher since 2005 with a short rush in the fourth quarter.

Stafon Johnson, the USC tailback who nearly died in a weightlifting accident that ended his season in September, was the last of USC's seniors to take the field in pregame introductions. Johnson, who wore his jersey and a stocking cap as he posed for pictures with his mother and teammates, still hasn't decided whether he'll attempt to return for another season.