Maggie Lucas shot 5 of 16 from the field and Alex Bentley went 8 of 21. To make matters worse, Nikki Greene played only 18 minutes because of foul trouble.
Faced with some adversity for the first time in a while, No. 8 Penn State kept the pressure on until No. 23 Michigan finally ran out of responses.
''We just didn't want to give them open shots. When they get open shots, they are a fantastic team,'' Lady Lions coach Coquese Washington said. ''We wanted to get them off the 3-point line and wanted to contest shots.''
Lucas finished with 19 points and Bentley added 16, but defense was the real story of Penn State's 59-49 victory over the Wolverines on Monday night.
Michigan shot 28 percent from the field and 6 of 26 from 3-point range, allowing the Lady Lions to take over sole possession of first place in the Big Ten.
Penn State (15-2, 5-0 Big Ten) and Michigan (15-3, 4-1) were the only teams in the league without a conference loss. The Wolverines kept it close before the Lady Lions went on a late 12-0 run.
Rachel Sheffer had 20 points and 10 rebounds for Michigan and surpassed 1,000 points for her career.
The loss snapped Michigan's 10-game winning streak, which equaled a school record. The Lady Lions have won nine straight.
Penn State led 47-46 before holding the Wolverines scoreless for over 6 minutes.
''It was a quality team, and they just wore us out,'' Michigan coach Kim Barnes Arico said. ''I guess that's why they're probably No. 8 and we're probably No. 23, because they had 4 more minutes in them than we did.''
The Lady Lions played much of the second half without the 6-foot-4 Greene, who picked up her fourth foul with 12:43 remaining. But the Wolverines, who entered shooting nearly 40 percent from beyond the arc on the season, couldn't take advantage.
Mia Nickson scored twice on moves inside during Penn State's decisive run, and when Bentley connected from the perimeter it was 55-46. The Lady Lions stayed aggressive on defense even as fouls mounted, keeping Michigan from finding a rhythm from 3-point range.
''It was an emphasis, because they're a great shooting team,'' Lucas said. ''We were trying to spy - especially Kate Thompson, because she's a great shooter.''
Thompson finished 3 of 16 from the field - 3 of 14 from 3-point range.
Penn State had barely been challenged recently in Big Ten play, beating Michigan State by 21 points, Nebraska by 22 and Wisconsin by 44 before Monday's game in Ann Arbor. The Lady Lions started impressively in this one too, going on an early 15-0 run capped by Dara Taylor's driving three-point play that made it 17-8.
Michigan pulled back within a point, but Penn State closed the half on an 8-1 run and led 32-24.
''They definitely bring the pressure a lot. They have three really quick guards that come in and they just hound you for days,'' Wolverines guard Jenny Ryan said. ''I think that it's a good learning experience for us.''
Michigan scored the first eight points of the second half, a run that began 29 seconds in when Greene picked up her third foul and left the game. Greene was called for a flagrant foul when she caught Sheffer around the neck and jaw with her left elbow.
After tying the game at 32, Michigan took a 35-34 lead on a 3-pointer by Thompson. Greene came back in the game and gave the Lady Lions a boost, but she picked up foul No. 4 and went back to the bench with Penn State up 40-35.
Even with Greene out, the Wolverines never did take the lead again. Lucas hit a 3-pointer off a nifty crossover move to put Penn State ahead 43-37.
