Katie Chin | Daily TrojanThe No. 5 Trojans are off to a 3-0 start, but so far each game has been contested in the comfort of the Coliseum. Now, the Trojans embark on the road for the first time this season in a matchup against a burgeoning program in Cal. “There is a mentality that I think you have to take [into road games] to not let the outside distractions come in,” head coach Clay Helton said. “Whether that is a different stadium, different locker room, crowd noise, getting on an airplane and traveling —sometimes it’s the first time for some kids getting on a plane.”As they head into Saturday’s matchup, USC has not lost to Cal since 2003 back when Aaron Rodgers was the Bears’ quarterback. The Trojans’ current winning streak is the longest in a century’s worth of games between the two California programs. While USC has dominated Cal for over a decade, the Bears now possess one aspect of the game they have not had in a long time: a solid defense under new head coach and former USC defensive coordinator Justin Wilcox.“He’s an unbelievable, brilliant coach,” Helton said. “And an aggressive coach. We figure that he will continue that aggressiveness versus us. He’s done it in the last three games.” Cal entered this football season with one of the toughest schedules in the nation (the 13th hardest according to Bleacher Report). Combine that with an inexperienced offensive line, the loss of prolific quarterback Davis Webb to the NFL, and the hardships of breaking in a new head coach, and it looked like the Bears would be on a fast track toward the very bottom of the Pac-12. Yet in Week 4, Cal stands at 3-0, with strong victories over North Carolina and Ole Miss primarily because of an aggressive, revamped defense. Finding statistics to illustrate just how bad Cal was on that side of the ball last year is not a difficult task. The Bears’ unit was the worst in the conference, as they gave up the most points (42.6) and second most rushing yards (272) per game. However, this year, Cal seems to be infused with new energy. Against Ole Miss, it forced three interceptions and sacked budding gunslinger Shea Patterson five times. Experienced Cal defenders like senior linebackers Devante Downs (leads the team in tackles, sacks and interceptions) and Raymond Davison III (23 tackles and two sacks) look like they are finally playing in a system that suits their talents and strengths. One storyline to watch will be how much Wilcox is able to decode USC’s offense given his time on the coaching staff just two years ago.“Justin [Wilcox] and I were together for two years,” Helton said. “So obviously he knows my personality and I know his.”Combine Cal’s defensive turnaround with its still-potent offensive attack (they were first in Pac-12 yards per game in 2016) led by running back Patrick Laird, and the Bears could be a dangerous threat to USC, which is still working out kinks on both sides of the ball. After running backs junior Ronald Jones and freshman Stephen Carr looked dominant against Western Michigan and Stanford, they were stifled in last week’s Texas game. The two combined for just 75 yards, as USC struggled to stay ahead of the chains. The Trojans were 6-of-18 on third down and came up short on all three fourth down attempts, partially due to a litany of drops from the receiving corps. Without effective running, the offense turned to redshirt sophomore quarterback Sam Darnold relying on his arm to make plays late in the game. “You’ve got to have that balance between run and pass,” Helton said. “If you commit to stopping the run, you have to be able to throw the ball … and then convert on 3rd-and-short with that run. Thank goodness the passing game came through that last game.”On the defensive side, USC will be challenged due to a slew of recent injuries. Junior outside linebacker Porter Gustin will be out indefinitely with a lingering big toe injury and a torn bicep. He finished with two sacks alone in the first half against Texas. While junior nickelback Ajene Harris returned to practice on Thursday, Helton was unsure if he’d be able to play a full game against Cal. Meanwhile, both senior outside linebacker Uchenna Nwosu and junior defensive tackle Rasheem Green have been dealing with nagging knee injuries.