Jeremy Ross returned the opening kickoff 54 yards and the Bears needed just two plays to score on a 27-yard touchdown run by Jahvid Best.
"We made kind of a mental bust," Wulff said. "It was something we prepared for. We still made the mistake."
While the bye week enabled the Cougars to regain some injured players, particularly on the offensive line, he also believes it was detrimental to their start.
"I think that not having live contact and tackling made an impact," Wulff said. "We've got to find some rhythm early. That's going to be the key to turning around the slow starts."
He said in the past that his inexperienced team has been too anxious at times trying to make plays early in games. Now, the Cougars face Notre Dame (5-2) on Saturday in San Antonio. Besides its current stable of players, the Irish have a presence stemming from a tradition that includes 11 consensus national championships and the third-most wins in college-football history.
Wulff said he hopes those factors do not distract his team, and that they would be addressed during practice this week.
"I think that we're going to play a football game like any other game," he said. "We need to focus on what we need to do. Spend too much energy on all the peripheral stuff and it becomes a problem."
Wulff has not been able to watch game tape on the No. 25 Irish yet, but said they are good in all three of the game's facets -- offense, defense and special teams. He noted their talent at quarterback with junior Jimmy Clausen, and that junior Golden Tate, who has 847 yards and eight touchdowns on 52 receptions, leads a strong receiving corps.
He believes the best way to counteract that is for the Cougars to mature.
"We want to take another step as a team," he said. "We want to raise the bar on our own expectations, so we can keep growing as a football team."
Wulff said he saw some of that against the Bears. True freshman Jeff Tuel, who was making his third start, completed 28 of 42 passes for 354 yards and two touchdowns. It was the second-most passing yards ever by a freshman behind Drew Bledsoe, who had 385 against Arizona in 1990.
Radio color commentator and former WSU coach Jim Walden repeatedly was complementary of the offensive line's pass protection against the Bears, but Wulff called it average to below average.
"He took too many hits," Wulff said. "He trusted his protection when it was there. He played more relaxed. You can tell he has good accuracy on the deep balls."
Wulff said Tuel still can improve, but is excited to see him develop along with the other young talent on offense.
"We've just got to keep growing around him," he said. "The guys around him are playing their first year of Pac-10 football. They're growing and taking steps together."
"We tried to get him in there a couple of plays and he didn't respond," Wulff said.