Mauer's pinch-hit two-run single capped a four-run eighth inning, helping the Twins rally for a 5-3 win over the Detroit Tigers on Friday night.
"This is a really big win for us," Twins manager Ron Gardenhire said. "Our guys grind, just like those guys grind. They come back and win ballgames, just like we do.
"Tonight we got the best of them at the end, and I expect it to be a battle all year."
With the bases loaded and two outs, Mauer lined a Joel Zumaya (0-1) pitch into shallow center to give the Twins their first lead of the game.
Detroit's starters are 6-2 this season, but Zumaya's loss dropped the relief corps to 6-8 with a 5.14 ERA.
"Our bullpen is struggling right now, there is no doubt about that," Tigers manager Jim Leyland said. "But we know we have good pitchers out there, and we know that we're not hitting, which leads to a lot of close games."
"We're not hitting," Carlos Guillen said. "When you don't hit, you shouldn't expect to win."
Nate Robertson allowed three runs and five hits in seven-plus innings for the Tigers, who led 2-0 after six innings.
Minnesota started the eighth with a Jason Bartlett walk and Nick Punto's single, bringing Zumaya out of the Detroit bullpen. Luis Rodriguez bunted the runners over, and Mike Redmond hit a two-run single off the right-field wall to tie it.
After a Michael Cuddyer double, Morneau was intentionally walked, loading the bases.
Zumaya struck out Torii Hunter before Mauer flared an inside pitch softly over Guillen at short and in front of Granderson in center.
"That was a good pitch, but he's a great hitter," Leyland said. "He fought it off and found an empty spot. Great hitters can do that. Lousy hitters can't."
Mauer's teammates weren't exactly surprised that he came up big.
"We might have to leave him on the bench just in case things like that happen in the eighth inning," Cuddyer said. "I got to second and Polanco says 'Oh god, that guy's coming up."'
Zumaya has allowed six runs in his last six outings, a stretch that he doesn't understand.
"I've never had anything like this happen before, which is why I'm kicking myself so hard," he said. "Usually, I'm hitting the corners, but right now I'm either walking guys or throwing it right down the middle."
- Ortiz gave up two runs and five hits with four walks in six innings. He had pitched at least seven inning in each of his first four starts.
- Monroe broke an 0-for-16 slump with a second-inning double.
- With Ivan Rodriguez (foot) unavailable, the Tigers were down to Rabelo as their only catcher. Although Inge was a full-time catcher early in his career, Tigers manager Jim Leyland said he would use INF Neifi Perez as the backup. Perez caught part of one inning for the Rockies in 1998.
- Hunter played despite a swollen mouth after being hit by a pitch in Thursday's win over Kansas City. "Torii's Torii," Gardenhire said. "He came in and said he was good to go. He's got a fatter lip than normal, but he played. Game on."