Redshirt freshman quarterback Sam Darnold takes the snap and rolls out as the pass rush closes in. He cuts upfield, finds daylight and breaks toward the end zone. But Darnold loses the ball as he dives for the goal line, killing the Trojans’ drive at the one-yard line.That was how USC’s first possession ended in Saturday’s game against Colorado. The Trojans eventually battled to a 21-17 victory over the Buffaloes, but they had to overcome four turnovers on the way — three from Darnold, who lost two fumbles and threw an interception. Only an excellent defensive performance allowed USC to drive down the field and score the go-ahead touchdown in the fourth quarter. When the Trojan offense opened the second half with turnovers on their first three possessions, the Buffaloes managed just a single touchdown thanks to a quickly forced three-and-out and an acrobatic interception from junior cornerback Adoree’ Jackson.To be sure, the Trojans didn’t have a poor offensive game. They racked up a season-best 539 total yards on offense, Darnold passed for a career-high 358 and junior wideout JuJu Smith-Schuster notched more than 100 receiving yards for the second straight week. Darnold even miraculously spun a fumble into a touchdown, scrambling in the red zone before finding sophomore tight end Tyler Petite near the pylon.“He’s able to make things happen that wouldn’t be available [for other players],” Petite said of his quarterback after catching two scores on Saturday. “He’s special.”And for that reason, head coach Clay Helton was hesitant to rein in his dynamic signal caller, despite Darnold losing the ball on several occasions.“When you have a kid with this instinct and creative ability, I don’t think you handcuff him,” Helton said. “I told him, ‘Drive it like you stole it.’ You play the game with no fear, and he does.”It’s easy to understand Helton’s sentiment, as USC has been a rejuvenated team since the 19-year-old replaced redshirt junior Max Browne under center. The Trojans have suddenly become fumble-prone, however, capping the offense’s potential. The team hasn’t exactly been a hallmark of ball security all season, but since Darnold’s first start against Utah, USC has fumbled 10 times in three games, losing six. Darnold is responsible for four of them (three lost), but two other Trojans — Jackson and senior tailback Justin Davis — have also put the ball on the ground multiple times.“As an offense, you’re not going to win a ton of games turning the ball over four times,” Darnold said. “It’s something we have to keep working on in practice.”Indeed, USC might need to correct the issue if the team wants a win at Arizona. The Wildcats have forced six fumbles this season, recovering four, and have five interceptions as a team—although they forced two-thirds of their turnovers this year in a single game against Grambling State. You have to go back a decade, to a 20-3 Trojan victory in 2006, to find the last contest between USC and Arizona that ended with a two-possession winning margin. The Trojans upset the No. 10 Wildcats during their most recent visit to Tucson in 2014, but it was only thanks to a shanked field goal that would have put Arizona ahead with seconds left to play.In a game that could very well go down to the wire, another afternoon like last Saturday could cost USC the game and the season, which can hardly withstand another loss with the Trojans’ middling 3-3 record and a brutal end-of-season schedule on tap. Fortunately, Darnold isn’t dwelling on any mistakes, and he isn’t lacking in confidence.“No matter what anyone else thinks, you just have to control what you can control. You can’t control the past. You just have to look ahead,” he said. “In the end, you just have to look ahead and take it play after play.”That’s exactly the attitude a head coach wants his starter to have as he encourages his team to have a “playoff mentality.” Helton said every week would be treated like a championship game from here on out, but as long as Darnold was continuing to progress, Helton won’t hesitate to let the redshirt freshman go through his growing pains.“There will be mistakes … but he’s one of those guys that you don’t make a robot,” Helton said. “I’m very proud of where he’s at. He’s not a finished product by any means, but he’s helping us win football games.”After all, in a playoff run, that’s all that matters.