AUSTIN, Texas -- A day after firing his defensive coordinator just two games into the season, Texas coach Mack Brown spent Monday trying to calm fan fears the program is in panic mode and teetering on the brink of a repeat of the losing season of 2010.

"You can look at it as panic," Brown said. "I'm trying to fix it."

Brown also insisted that the 40-21 loss to BYU -- in which Texas gave up an astounding 550 yards rushing -- didn't raise any pressure on his own job.

"When you lose at Texas, you're going to be bashed. I accept it," Brown said.

Texas is 24-17 since losing to Alabama in the national championship game after the 2009 season, but Brown had talked openly in before this season about high expectations, that this year's team could return the program to national prominence.

But an embarrassing road loss on national television exposed a defense that is still seriously flawed, and sent Texas tumbling from No. 15 out of the Top 25. Texas (1-1) hosts No. 25 Mississippi (2-0) on Saturday.

Brown, who had never before fired an assistant in midseason, seethed over the loss and declared immediately after the game he would evaluate Manny Diaz's job when he watched game film. Brown watched it twice overnight and fired Diaz on Sunday.

Brown has turned the defense over to Greg Robinson, who spent one season as the defensive coordinator in 2004 before leaving to become the head coach at Syracuse. Robinson also spent 14 seasons in the NFL and coached Michigan's defense for two years.

Brown said he fired Diaz after just two games to avoid a repeat of the first half of the 2012 season when the Texas defense was riddled by Oklahoma State, West Virginia and Baylor and struggled to stop the run.

"I wasn't going to let that continue," Brown said.

But Brown's move also led to questions why it wasn't done sooner.