ANN ARBOR, Mich. — Tommy Carr jogged onto the same field where his grandfathers led a national championship team and set the school record for career interceptions, and the crowd roared.

And he made the most of the opportunity.

Carr converted a third down with a 12-yard touchdown run with 2:58 left to play, giving Michigan a two-score lead it needed in a 21-18 win Saturday over Penn State.

“To score that touchdown to seal the game was huge,” he said.

The Wolverines (4-2, 1-2 Big Ten) needed the win to avoid losing their first three conference games in a season for the first time since 1967.

It might not have happened if first-year coach Kyle Whittingham didn't agree to bench Bryce Underwood at halftime and give Carr a chance to turn around a lackluster offense and perhaps fire up a listless team.

“The idea at halftime was to create a spark, and Tommy did just that,” Whittingham said.

Michigan will face a big test next week at home against No. 5 Indiana. Whittingham wasn't ready to say who would start at quarterback in that game.

Tommy Carr’s brother is Notre Dame quarterback CJ Carr, grandson of 1997 national championship winning coach Lloyd Carr and All-America defensive back Tom Curtis, a former Wolverine who set a program record with 25 interceptions. Tommy Carr is the son of Michigan graduates, including former walk-on quarterback Jason Carr.

Lloyd Carr attended the game and said, “Wow,” after his grandson ran for a touchdown.

“Can't wait to see him,” Tommy Carr said.

Michigan suddenly had success on offense after Carr entered the game to cheers and Rocco Becht threw two interceptions, taking a 14-3 lead in the third quarter on Bryson Kuzdzal's 43-yard touchdown run and Jordan Marshall's 1-yard run for a score that was set up by Carr's 22-yard draw.

The Nittany Lions (3-4, 0-4) pulled within three points early in the fourth on Carson Hansen's 2-yard touchdown run and a two-point conversion.

They had the ball with a chance to drive for a tie or the lead, but Becht lost a fumble at the Penn State 16 to set up Carr's touchdown run.

“This game is super humbling,” Becht said.

Becht bounced back with a 24-yard touchdown pass to Chase Sowell with 1:11 to go, pulling the Nittany Lions within three points again.

Michigan recovered the onside kick, sealing the win.

Underwood threw two interceptions in the second quarter against Penn State. It was his fifth interception in three games and sixth this season, surpassing his total of five passing touchdowns.

“Bryce couldn’t have handled it any better,” Whittingham said.

Penn State: Matt Campbell was hired to turn the program around after James Franklin was fired a little more than a year ago, but the former Iowa State coach has lost four straight games just as the team did last year during a six-game skid.

“We’re not where we want to be, but I believe this group is pounding away," Campbell said.

Michigan: The decision to put Carr in and take Underwood out of the game may have helped the program avoid starting 0-3 in conference play since the year before the Bo Schembechler era began.

Penn State: After a bye week, hosts Purdue on Oct. 31.