No. 11 USC will have a chance to play for its first Pac-12 title since 2008.

The Trojans used a four-touchdown burst in the second and third quarters to beat Colorado 38-24 Saturday at Folsom Field, winning the Pac-12 South and securing a spot in the league title game.

The Trojans (9-2, 7-1 Pac-12) got two passing touchdowns and a 24-yard rushing score from quarterback Sam Darnold in their mid-game deluge. Coupled with an Ajene Harris interception return for a touchdown just before halftime, USC built a 27-0 lead, shaking off a sluggish offensive start.

"They already tried hitting me with out (routes) off of rubs. That opportunity I had to jump the ball, and that's what I did to help my team out," Harris told the USC Trojans Radio Network in his postgame interview.

Darnold settled in to finish 21-of-34 passing for 329 yards. His scores went 10 yards to Michael Pittman Jr., and 18 yards to Deontay Burnett.

Burnett caught six passes for 79 yards, and Pittman added four catches for 59 yards. Steven Mitchell led the way with four receptions for 91 yards.

Freshman wide receiver Tyler Vaughns caught five passes for 90 yards, including back-to-back acrobatic catches on a scoring drive in the pivotal second quarter.

USC head coach Clay Helton said Darnold "did a great job not forcing anything" in the passing game. Darnold has been interception-prone, throwing at least one in eight of 10 previous games, but he went without a pick on Saturday.

With running back Ronald Jones II eclipsing 100 yards for the third consecutive game, the Trojans' offense achieved the kind of balanced look Helton says he favors.

"He finds yards that just aren't there," Helton said of Jones on the running back's 142-yard day. "He's just special. He is the balance this offense needs."

USC won the Pac-12 South a season after Colorado (5-6, 2-6) was the surprise winner. The Trojans get just their second shot at the conference title game since its inception in 2011. They lost the 2015 Pac-12 Championship Game to Stanford, 41-22. Several members of that team remain in 2017, providing some additional motivation.

"(Winning a conference championship) means a lot," Harris said. "It hasn't been done in a lot of years. We feel like we're the ones (who) are going to turn this program around."

Its hope of returning to the Pac-12 Championship Game long ago dashed, Colorado came into Saturday's contest playing for bowl eligibility. The Buffaloes kept those hopes alive in the early going.

USC's first drive ended with placekicker Chase McGrath, limited in practice this week by injury, missing a 40-yard field goal. The next saw Colorado stuff running back Aca'Cedric Ware on a fourth-down conversion attempt.

Forcing a punt on USC's third drive, the Buffs appeared poised to spring the potential upset on their senior day. But USC's eruption before halftime gave the Trojans enough breathing room, despite Colorado twice shaving the deficit to two touchdowns in the second half.

The Buffs scored on Steven Montez passes of 79 and 57 yards to wide receiver Juwan Winfree. Running back Phillip Lindsay's goal-line touchdown in the third quarter brought Colorado within 13 -- the closest it had been since USC's 27-0 run -- but a McGrath field goal and a 22-yard touchdown run by Jones extended the lead to three touchdowns with 8:46 left in the game.

Winfree's second touchdown reception brought the game to its final score.

Colorado had other scoring opportunities, but James Stefanou had two field-goal attempts blocked. Austin Jackson got to one for the Trojans, and Brandon Pili the other. Colorado coach Mike MacIntyre said Stefanou's low kicks were the issue.

"We made some critical mistakes and kind of gave them the game," McIntyre said. "They're the most talented team in the our league, year in year out, no doubt it, and we had some opportunities tonight and squandered it away."

NOTES: USC RB Ronald Jones II passed LenDale White, Reggie Bush and Mike Garrett to become the program's sixth-leading rusher at 3,292 yards after Saturday's 142-yard performance. ... Colorado QB Steven Montez passed for at least 345 yards for the third consecutive game with 376. He tallied 347 on Oct. 28 vs. Cal, and 345 on Nov. 4 at Arizona State. ... USC converted 1 of 3 fourth-down conversion attempts. The Trojans came into Saturday's game ranked No. 111 in FBS in fourth-down conversions at 35.3 percent. ... Colorado RB Phillip Lindsay was named recipient of the Buffalo Heart Award after the game, an honor voted on by fans to recognize the team member with the most inspiring attitude.