The Trojans started off slow, then scored 28 unanswered points to claim a lead that would not be taken away from them against No. 19 Colorado on Saturday night in a 31-20 win at the Coliseum. The win propelled USC into first place in the Pac-12 South, with a 3-1 conference record and 4-2 mark overall.Twenty-one of those points came in the second quarter. USC’s fire ignited after Colorado scored the first touchdown of the game, when sophomore wide receiver Laviska Shenault Jr. took the snap on the 49-yard line and ran it all the way out of a Wildcat formation.USC redshirt sophomore wide receiver Velus Jones responded immediately with a 31-yard kickoff return to open the drive that would end with a 27-yard pass from freshman quarterback JT Daniels to redshirt sophomore receiver Tyler Vaughns in the end zone, putting the Trojans on the board. Vaughns set up his touchdown with a 28-yard reception.USC celebrates after a touchdown. – Josh Dunst | Daily TrojanOn USC’s next drive, Daniels launched a pass 65 yards to junior wide receiver Michael Pittman in the end zone to give USC its first lead of the game. Colorado responded with a drive that failed to pick up any yards. Daniels came back out and threw to Pittman again for a leaping 39-yard catch. Pittman ended the drive fittingly with another catch in the end zone to score a touchdown, extending USC’s lead to 14 with one minute left in the half.“I feel like the offense is taking steps on making those explosive plays,” Pittman said. “We showed some good things tonight to move forward.”Daniels threw two interceptions in the first quarter, with the first coming on the first snap of the game and seemed to have no Trojan receivers in the area. It took until the fifth drive of the game for USC to record a first down on a 12-yard reception from Pittman.The second interception was forced by Colorado senior safety Evan Worthington when he threw a pass downfield with two minutes left in the first quarter intended for freshman receiver Amon-Ra St. Brown.“It was neat to see the quarterback tonight have a couple mistakes and then just settle in,” head coach Clay Helton said. “It wasn’t all the way perfect but he really was putting balls to the right people … He found the one-on one matchups, … put the ball up decisively and believed in his guys.”The first quarter consisted of nine possessions and ended with neither team entering the red zone and no score on the board. USC’s defense held Colorado to two first downs in the first quarter and one rushing yard, while the offense failed to convert a third down. The Trojans finished the first half with no rushing yards on 11 attempts, but had 255 passing yards compared to Colorado’s 20. Redshirt senior cornerback Ajene Harris tipped a pass from junior quarterback Steven Montez and bobbled the football before running it six yards into the endzone to bring some life to the third quarter and to give the Trojans a 21-point lead. He tied a school record with his third career pick-six.“I saw them keep trying to throw under routes to [Shenault], and I had a chance to jump at that time,” Harris said. “I had seen it was thrown behind him and he bobbled it. I tried to secure it as fast as I could and get it into the end zone.”Tyler Vaughns catches the Trojans’ first touchdown of the night against Colorado – Josh Dunst | Daily TrojanThe quarter ended still without an answer from Colorado. The fourth quarter saw two penalties in a row from USC that pushed Colorado close to the end zone. They inched forward and scored a touchdown on a two-yard rush from senior running back Kyle Evans, their first points since the first quarter. The Buffaloes closed within two scores after another touchdown, but the Trojans hung on for the win.The Trojan defense held Shenault to 72 yards on nine carries and senior running back Travon McMillian to 43 yards. “Defensively, it was a tremendous effort,” Helton said. “Anytime you have 16 tackles for loss in a game, it just felt like the defense was playing in Colorado’s backfield all night. [Senior linebacker Porter Gustin] had the numbers, but we challenged the rest of our kids to be aggressive to the ball, to force the quarterback to have an off-night. I thought they took the challenge.”Senior linebacker Cam Smith was out with a hamstring injury, placing the leadership responsibilities on redshirt junior John Houston. “I prepared for it,” Houston said. “I prepare for it everyday, every practice. I try to call all of the calls while [Smith] is in there, just to make sure I’m on the right stuff.”USC’s four sacks on the night started with Colorado’s first drive of the game when Gustin sacked Montez on third down. Gustin and redshirt senior defensive lineman Malik Dorton combined for another sack for a nine-yard loss right before Harris’ pick-six. Redshirt sophomore defensive lineman Liam Jimmons added a sack in the second quarter to push Montez back nine yards and prevent the Buffaloes from finding a first down, along with junior linebacker Jordan Iosefa’s six-yard sack early in the fourth quarter on third down. USC’s defense held strong against Colorado on Saturday – Josh Dunst | Daily TrojanGustin went down on the field with a right ankle late in the fourth quarter. He was carted through the tunnel and hopped on his left leg into the locker room. He came out with crutches and a boot on his right foot.Freshman linebacker Palaie Gaoteote found out he would be starting on Friday, so he took the two days to intensively prepare and watch film. He left in the third quarter with concussion-like symptoms after a hard hit and did not return to play, but still finished as USC’s leading tackler with nine tackles. He said the hit knocked himself out. “I showed a lot of instinct, a lot of tenacity,” Gaoteote said. “I just expected to be a team player.”USC finished the night with 13 penalties for 123 yards, which was not much of an improvement from the 18 penalties for 169 yards against Arizona.“We haven’t put together a complete game,” senior safety Marvel Tell said. “We haven’t reached our potential yet.”The Trojans will travel to Utah to continue Pac-12 play on Oct. 20 at 6 p.m.