LOS ANGELES (AP) -- Just when it appeared Arizona was making a game of it, Southern California got it together.
A few minutes later, the outcome was decided.
LenDale White ran for 118 yards and three touchdowns, Matt Leinart passed for 280 yards and three more scores, and No. 1 USC beat outmanned Arizona 49-9 on Saturday night.
By winning their 19th straight game, the Trojans clinched the Pac-10 championship for the second straight year along with a berth in the Rose Bowl.
USC (10-0, 7-0 Pac-10) leads No. 5 California by one game with one remaining, but is the conference champion by virtue of its 23-17 victory over the Golden Bears last month.
"This is just a wonderful accomplishment for our program," USC coach Pete Carroll said. "At this point, we've done everything we can do with the season. So dear to our hearts, so important to our program, so important to our conference -- when SC's in the Rose Bowl, it seems just right."
That won't happen in the best case scenario because the Trojans have an opportunity for much more. If they beat Notre Dame and UCLA in their last two games, they almost surely will play for the national championship, to be contested in the Orange Bowl.
Arizona drew within 12 points late in the third quarter, scoring its only touchdown after USC's third lost fumble of the game.
But the Trojans responded by scoring three TDs in the next seven minutes to put the Wildcats away.
USC's latest triumph also extended its winning streak in Pac-10 games to 14, and its winning streak at the Los Angeles Coliseum to 20. That ties the school record for consecutive victories at home, accomplished twice in the 1920s.
The Trojans have won 30 of their last 31 games and six this season by 30 or more points.
White, a 6-foot-2, 235-pound sophomore from Denver, scored on runs of 3, 2 and 6 yards, giving him 15 touchdowns in 10 games this season and 29 in 23 games overall.
"Our line wanted to run the ball, they wanted to prove something today," he said. "Coming in, they kept hearing that they're only getting 3 yards a carry. And we wanted to prove we could run the ball when we wanted to and how we wanted to."
Leinart completed a career-high 27 passes in 35 attempts including 11 straight at one stage and wasn't intercepted. He has thrown 23 scoring passes this season, 61 in his career and two or more in 21 of his 23 collegiate starts.
Favored by 35 points, the Trojans stumbled a bit offensively in the first half, falling behind early, blowing two scoring opportunities and leading just 14-3 at the intermission.
The second half was a different story.
White scored his second touchdown to cap a 76-yard drive with the second-half kickoff, making it 21-3.
Arizona (2-8, 1-6) scored its touchdown on a 9-yard pass from Richard Kovalcheck to Steve Fleming with 4:55 left in the third quarter.
The score was set up by Wilrey Fontenot's recovery of a fumble by Reggie Bush at the USC 40. Syndric Steptoe ran 31 yards on a reverse before the scoring play, which drew boos from some in the Homecoming crowd of 80,167.
That's when the Trojans exploded. White scored for the third time to cap a 78-yard, five-play drive before Leinart threw scoring passes of 13 and 12 yards to freshman Dwayne Jarrett, who had six catches for a career-high 144 yards.
"Arizona did a nice job of giving us some problems early in the game," Carroll said. "But by the third quarter, we got control of it, and we left no doubt once we got to the fourth."
Hershel Dennis scored on a 1-yard run with 7:27 remaining to complete the scoring.
Nick Folk's career-long 48-yard field goal on Arizona's second possession gave the Wildcats an early lead.
It didn't last long.
Leinart threw a 5-yard pass to David Kirtman on the first play of the second quarter to put USC ahead for good. The key play of the Trojans' 57-yard drive was a 10-yard pass from Leinart to Alex Holmes on fourth-and-3 from the Arizona 27.
White's first touchdown with 2:54 left in the second quarter made it 14-3. He scored one play after freshman tailback Desmond Reed took a handoff from Leinart and threw a 55-yard pass to Jarrett.
Kovalcheck completed 15 of 32 passes for 165 yards with two interceptions. Mike Bell led the Wildcats in rushing with 74 yards on 15 carries.
"They're the No. 1 team in the nation and they played like it," first-year Arizona coach Mike Stoops said. "They're the best I've ever coached against. They made it look easy. We got outplayed and outcoached. They were running downhill at us the whole second half. We fought all we could just to keep it close."
Arizona drove into USC territory on its first two possessions and recorded five first downs before the Trojans got their first one. But the Wildcats did very little offensively after that.
"We were well-prepared. They were just too good," Fleming said.