SOUTH BEND, Ind. — San Diego State coach Chuck Long was asked after giving Notre Dame a scare who was better, the Fighting Irish or Cal Poly, which beat the Aztecs a week earlier.

“That’s a tough question,” Long said, chuckling a bit at the question. “It’s hard to say who’s better. They both beat us.”

That might say as much about Notre Dame’s play in a 21-13 come-from-behind victory as the Fighting Irish’s four turnovers and struggles to establish a running game against a makeshift San Diego State defensive line.

San Diego State (0-2), a 21-point underdog that opened the season by losing to an FCS team, appeared to be on the verge of an upset early in the fourth quarter.

Brandon Sullivan was inches away from a 4-yard touchdown run and a two-score lead for the Aztecs. But safety David Bruton jarred the ball loose and recovered it in the end zone to help the Irish (1-0) avoid an embarrassing loss.

“They had a chance to put the game away,” Notre Dame coach Charlie Weis said.

Still, Weis told his players they should be happy with the victory.

“The guys will come in here and everyone will talk about an ugly win. Are you happy with an ugly win? I told them, ’Yes, you’re happy with an ugly win because it’s better than an ugly loss,” he said. “I’ll take an ugly win any day of the week.”

Moments after the crucial fumble by San Diego State, Jimmy Clausen threw a 38-yard touchdown pass to Golden Tate. Clausen was 5-of-5 passing for 76 yards on the drive to rally the Irish to victory, as they avoided losing back-to-back season-openers at home for the first time since 1887-88, its first two seasons of playing football. Clausen added a game-clinching 6-yard TD pass to David Grimes with 2:08 left.

Clausen, who also had a 22-yard TD pass to freshman Michael Floyd late in the first half, was 21-of-34 passing for 237 yards with two interceptions.

“We’ve come a long way since last year,” Clausen said. “We didn’t panic when we were down in the fourth quarter and we needed a score, we needed to get points on the board. We just rallied together.”

Ryan Lindley carried San Diego State’s offense, completing 29-of-59 passes for 274 yards with one interception and scoring a touchdown on a 1-yard keeper.

“He continues to amaze me every game he plays and he’s only played two games. Every practice he seems to get better,” Long said.

For much of the game the Irish didn’t look significantly better than last year’s 3-9 squad, as they trailed most of the way and repeatedly made mistakes at key times. Robert Hughes fumbled the ball away on San Diego State 3 and linebacker Luke Laolagi recovered. Later in the second quarter, Tate was open in the back of the end zone but Clausen’s pass was wide of the mark.

The Irish also missed a 48-yard field goal wide right, and failed to get a second attempt off when holder Eric Maust muffed the snap.

The Irish defense made its share of mistakes, too. Defensive captain Maurice Crum was called for a flagrant pass interference, then three plays later on a late hit on the quarterback to keep a drive alive, although the Aztecs still didn’t score.

San Diego State did finally score, though, after Lindley connected with a Darren Mougey on a 43-yard pass play. Mougey, who had five catches for 97 yards, was wide open at 30 and was tackled at the 1 by Bruton. Lindley scored a play later on a keeper.

The Aztecs went ahead 13-7 midway through the third quarter on 80-yard scoring drive with Lindley completing 6 of 7 passes for 49 yards, capped with a 15-yard pass to a diving Mougey in the back of the end zone.

But it was still a marked improvement over last year, when the Irish had -14 yards rushing through three games. The Irish finished with 105 yards on 34 carries.

Notre Dame defensive end Pat Kuntz said the Irish should just enjoy the victory.

“Sure, we would have liked to win in a different fashion today,” he said. “But that’s the benefit of playing San Diego State in the first game.”