Alex Bentley had 11 points and four steals, and set the emotional tone in the final appearance at the Jordan Center for the vocal guard and the other four seniors who helped bring the Lady Lions (23-3, 13-1) back to Big Ten prominence.
After trailing by 19 early, Michigan (19-8, 8-6) clawed back to within four with 8 minutes left with the help of two 3s from Kate Thompson (25 points) during a 12-4 second-half run.
Penn State turned to defense to hold on and finish unbeaten at home. The Lady Lions nearly frittered away an early big lead built during an 18-0 run in the first half.
All Penn State needs now is to beat Minnesota on the road Thursday night to clinch the conference crown outright.
Michigan lost its second straight to a ranked foe after getting blown out by No. 24 Nebraska at home 57-39 on Thursday. They entered Sunday in a three-way tie for fourth in the Big Ten and the last spot for an important first-round bye in the conference tournament next week.
Nya Jordan added 14 points and 10 rebounds for Michigan. Thompson was 5 of 13 from 3-point territory, and the nation's leader in 3-point buckets (3.69 per game) helped narrow the huge deficit to a two-possession game midway through the second half.
But the Lady Lions staved off Michigan, fueled by a sea of vocal fans wearing pink for the annual Pink Zone game to raise money breast cancer causes.
The second-half stretch turned into a defensive struggle, with both teams fighting to get shots off in time.
Ariel Edwards (11 points) gave the Lady Lions the break they needed on offense, hitting a 3 from the wing just before the shot-clock buzzer sounded for a seven-point lead with 7:11 left.
With the Jordan Center rocking, it was Penn State's turn to turn up the defensive pressure. Tori Waldner blocked Branae Harris' off-balance jumper in the lane with the shot clock winding down, and Bentley followed at the other end with a jumper from the top of the circle for a 57-48 lead with 6:25 left.
A game after shooting a season-low 27 percent in the loss to the Cornhuskers, Michigan wasn't much better against Penn State after shooting 35 percent (19 of 54). The Lady Lions also held a 43-32 advantage on the boards, including nine from senior Nikki Greene.
Michigan just couldn't recover from Penn State's big first-half run, during which the Wolverines went seven minutes without a field goal. Penn State already had a 23-4 lead by the time Thompson hit a 3 with 8:25 left in the half to end the drought.
Lucas provided the early offense, notching 15 points in the first half on 5-of-11 shooting and 3-of-8 from 3-point range. She finished 7-of-17 shooting for the afternoon.