Defense wins championships.We all know that saying. I think it’s probably been plastered onto so many high school football shirts and motivational posters that anyone who’s ever watched or played or even been around sports knows it. Offense wins games, but defense wins championships.No matter what sport, I’ve always loved defense, perhaps even more than offense. When I played basketball and soccer, there was something satisfying about squaring up an opponent and shutting down any move they tried to make past you. When I watch football and basketball, I live for the hard hits and the showboat blocks.That might be because of where I’m from. Kansas City is known across the board for teams that specialize in defense — Sporting KC with its indomitable home field atmosphere, the Chiefs with their smash mouth defensive line and Alex Gordon and the Royals and their high-flying antics in the outfield. It’s something the teams and the city takes pride in. And when defense is great, it’s a thing of beauty to watch.Last Saturday, I don’t think I could use the word “beautiful” to describe most of the USC defense. There were, of course, the highlights of the fourth quarter — that Porter Gustin sack, the Marvel Tell interception — but the game left a bitter taste in the mouths of most fans despite the 49-31 final score.Entering this season, there has been perhaps too much hype surrounding this USC football team. Yet most of it focused on phenom quarterback Sam Darnold, his offense and his inevitable quest to collect a Pac-12 championship, a national championship and a Heisman trophy in one fell swoop. There was a slight rumble in the Coliseum when Darnold took the field for the first time on Saturday, a thrum of expectation that paid off in the opening touchdown drive and then quickly dissipated throughout the frustrating first half. And despite receiving very little of the offseason spotlight, the same expectation still stood for the defense as it took the field.What unfolded over the first three quarters of the Western Michigan game was, in a word, disappointing. The defensive line found no room to pressure the quarterback, while the secondary blew coverage and the linebackers let running backs slip away with sloppy arm tackles. The offense struggled to get off the ground, but they also had no safety net. The defense allowed 263 yards on the ground alone, falling to 113th out of 125 teams in the FBS after the poor outing. The hits weren’t hard and the stops weren’t impressive. For the first time, I felt that the best way to describe the USC defense was “soft.”There are a lot of excuses that could be made for the defense. Western Michigan was bringing a new head coach, offensive coordinator and quarterback to the Coliseum, and there was little to no film available to prepare the defense. Junior linebacker Cam Smith, who typically leadsin-game adjustments for the Trojans, was confined to the locker room for the first half due to a suspension carried over from the Rose Bowl, leaving the young defense to adjust themselves without one of their captains. For all those reasons, it makes sense that team came out to a slow start. But there’s a difference between a slow start and allowing almost 300 yards rushing. Sloppy tackles and lack of energy couldn’t be blamed on a lack of film or a sidelined leader or even the heat. Smith was harsh in his review of the team, saying it had nothing to do with anything except lack of concentration.“Bad,” he said impatiently to the reporter scrum after the game. “It was really bad.”Something has to change. The Trojans squeaked out of their season opener with a victory, but the same performance can’t be repeated next Saturday against Stanford. The Cardinal will bring everything that Western Michigan did — scrappy defense, a hard-nosed run game and balanced aerial attack — with the added benefit of Pac-12 talent. It’s too early to panic, and first games are historically poor barometers for the future success of football teams. (Just ask any fan who stuck through from the Alabama game to the Rose Bowl last year, if you don’t believe me.) But while many might be ready to sound the alarm while poring over Darnold’s Heisman chances, I’m much more concerned with the defense.Defense wins championships. It’s cliché. It’s also true. And as USC continues to grind through a tough Pac-12 and non-conference schedule — all without a bye week — it will be the defense, and not the offense, that will be tested the most.If the Trojans are going to live up to the hype this year, fans will have to hope that a different defense shows up to the Coliseum this Saturday.Julia Poe is a junior studying print and digital journalism. She is also the sports editor of the Daily Trojan. Her column, Poe’s Perspective, runs Wednesdays.