Daniel Zhu | Daily TrojanUSC’s highly anticipated 2017 football season kicked off in a lackluster way on Saturday, as heavy underdog Western Michigan went blow-for-blow with the Trojans, who were unable to pull away until the fourth quarter. For a top-five team, the mere possibility of losing to a Mid-American Conference team in the opening weekend was disappointing.This week brings a much greater challenge; the 14th-ranked Stanford Cardinal come to the Coliseum for a rivalry game after pounding Rice 62-7 two weeks ago. Here are the key areas the Trojans will have to improve on to defeat Stanford for the first time since 2014.Stop The RunWestern Michigan ran for 263 yards on Saturday, on 5.5 yards per attempt. The Trojans were unable to get a push from their defensive line, and the result was consistent openings for Bronco running backs. USC’s lack of physicality was evidenced by the four tackles for loss and one sack during the afternoon match.The front line wasn’t the only issue. Trojan linebackers and defensive backs missed a lot of tackles in the secondary. USC struggled to track down and wrap up open-field runners.This type of play will be an issue against a Stanford team that bludgeoned Rice for 287 rushing yards on 8 yards per attempt. The Cardinal have four returning starters along the offensive line, and they looked dominant in Week 1. USC’s run defense must be tougher, not only this week, but also moving forward.Darnold needs to take the helmTo be clear, Darnold wasn’t bad on Saturday. He was 23-of-33 for 289 yards, ran for a touchdown and converted on six of his eight third down attempts. He made the plays the team needed, and did the best he could behind a slightly spotty pass-blocking offensive line.However, the type of performance that can down Western Michigan isn’t the same as the one that is necessary to defeat Stanford. Darnold’s two interceptions, while coming on tipped balls, were not placed in the right spot for receivers to make plays. He lacked chemistry with every receiver but junior Deontay Burnett, missing multiple throws downfield on miscommunications, and he didn’t throw a touchdown.Darnold was far from USC’s biggest problem Saturday. But Stanford’s defense will be much stouter than Western Michigan’s. They won’t let junior Ronald Jones II and freshman Stephen Carr run over, around and through them. The receivers likely won’t gain any more separation. For the Trojans to win, Darnold will need to make plays with his feet and complete tough throws. He needs to prove he is worth the hype.Cut Down On MistakesIssues of discipline plagued the team last season, especially during the 1-3 start, and it was the same story Saturday. The Broncos scored touchdowns on a double pass and a kick return, which were key in maintaining an early lead in the second half. Junio linebacker Porter Gustin was inches from intercepting the double pass and taking it to the house, but once quarterback Jon Wassink had the ball in his hands, he had a clear path to the end zone. The team committed two turnovers on Darnold’s interceptions, and it would have been three if the Broncos recovered an errant snap. The Trojans were penalized nine times, including four on the offensive line, for a total of 94 yards. The line’s communication struggles were apparent on a third down sack in which the pass rusher reached Darnold untouched. Receivers dropped no fewer than four Darnold passes, and sophomore cornerback Jack Jones set the Trojans back when he let his knee touch the ground while receiving a kick. These type of unforced errors will be deadly against an opponent of Stanford’s caliber, and the Trojans will be embarrassed at home if they don’t clean up their act.