BIRMINGHAM, Ala. (AP) — The Mississippi State Bulldogs avoided the controversy that would have ensued had they lost to winless Alabama-Birmingham. But in the process, they might have created a quarterback controversy.

Backup quarterback Tyler Russell replaced an ineffective Chris Relf to start the second half and threw three touchdowns to help Mississippi State overcome a 3-0 halftime deficit and defeat UAB 21-3 on Saturday.

With Relf at quarterback, the Bulldogs (3-3) had 118 yards in total offense in the first half and punted five times. After the change was made to Russell, who had played in only two of the first five games this season, MSU gained 298 yards and punted only once.

“It wasn’t that Chris was playing poorly. I just felt we needed a spark,”

MSU coach Dan Mullen said. “I guess putting Tyler in was the best thing I could do to try to create a spark. He came in and played exceptionally well. He had a lot of energy.”

On his second possession, Russell led the Bulldogs on a seven-play, 89-yard touchdown drive. The score came on an 18-yard pass to Marcus Green, who out jumped UAB linebacker Lamanski Ware for the ball at the 4-yard line and ran in for the touchdown.

Russell followed that with fourth-quarter touchdown passes of 57 yards to Chad Bumphis and 20 yards to Malcolm Johnson. He finished with 166 yards on 11-of-13 passing, including a stretch of eight consecutive completions.

“He (Mullen) just said he was going to give me a shot to start the second half,” Russell said. “Once I got that first completion, I calmed down and just played football.”

Mullen decided to make the change after watching the Bulldogs get shutout in the first half by a UAB team that had allowed an average of 35 points per game this season.

MSU’s only scoring threat in the half ended when Relf was sacked for an 11-yard loss, and then Derek Depasquale missed a 32-yard field-goal attempt. After that, UAB (0-5) held the Bulldogs to a total of 59 yards on their next five possessions of the half.

“We were a little flat in the first half,” Mullen said. “Everyone was looking around for somebody else to make the play.”

Relf, who had only 46 yards passing in the first half, did not complain about the switch to Russell, though he said the offensive game plan seemed to open up more in the second half.

“I just think we need to throw the ball down the field more. I didn’t have that chance and Tyler did,” Russell said. “He made the big throws. I’m just happy with the win.”

Five of MSU’s first seven plays to start the second half were passes. And though the Bulldogs ran the ball more often once they gained the lead, with Vick Ballard finishing with 101 yards rushing, the initial change in strategy was noticeable to the Blazers.

“It seemed they opened up their playbook a little more when they put (Russell) in,” UAB cornerback Cornelius Richards said. “He threw the ball a little more than (Relf).”