LOS ANGELES - Even as the No. 1 team in the country, Southern California has things to work on. Like too many penalties and those slow starts that force the undefeated Trojans to rally.

Sure, it’s exciting for the fans, but needing big second halves to win the last three weeks can eventually take its toll.

That’s why the Trojans (5-0) will try to correct their mistakes this week before heading to South Bend, Ind., for a big game against No. 9 Notre Dame (4-1).

“We’ll be up for them and they’ll be up for us,” quarterback Matt Leinart said after USC defeated pesky Arizona 42-21 Saturday for its 27th consecutive victory, best in the nation.

“It’s a great stadium and there’s a lot of tradition in the rivalry, but we’re going to treat it like any other game. That’s how we do it. We don’t care if it’s Notre Dame, Oklahoma, Arizona, whoever. It doesn’t matter,” said Leinart, who is 30-1 as a starter.

Penalties have dogged the Trojans recently. While preparing to play Arizona, they emphasized cleaning up the miscues, and they did somewhat. USC had six penalties for 60 yards Saturday, nearly half of what it had in games against Arizona State and Oregon.

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Coach Pete Carroll said Saturday’s performance was better, then added, “That (turnovers) is what it takes to disrupt a rhythm. That’s not characteristic of the way we want to play.”

Arizona also exposed some deficiencies for USC’s special teams. The kickoff unit gave up five returns for 159 yards, including a 76-yarder to Syndric Steptoe in the third quarter that set up a touchdown for the Wildcats, who trailed 28-21.

Carroll acknowledged that the Trojans didn’t earn any style points.

“There are prettier ways and more comfortable plays, but I don’t worry about that,” he said. “I don’t care how we win. I just like getting wins.”

The Trojans started slowly for the third straight week, and led by just a touchdown entering the fourth quarter. They scored twice in the fourth to put the game away.

“Coach Carroll champions the call of finishing. That’s the motto of this team,” linebacker Oscar Lua said. “Everything we do from warmup to the game, it’s ingrained in our training.”

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Leinart threw for 360 yards, two touchdowns and one interception, which ended a drive. The Trojans also had a fumble in the first half, when they led 14-7.

One area that continued to produce was the running game. Tailbacks LenDale White and Reggie Bush each topped 100 yards for a school-record third straight game.

White scored a career-high four touchdowns and ran for 179 yards; Bush added 110 yards despite twisting his right knee in a pileup in the first quarter. He didn’t score for the first time in five games.

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The injury, described as a minor sprain, caused soreness, but Bush said he didn’t expect to miss any time.

“We hadn’t had the running game in our focus and they came out exploding,” Lua said. “They did a great job.”

The Fighting Irish were idle Saturday, so they’ll have had two weeks to prepare for the Trojans.

“We can’t control the intangibles and the environment,” safety Ryan Ting said. “But as long as we keep doing our job and doing things right, then there’s no stopping us.”