The Spartans (25-6, 16-4 Big Ten) earned a share of the Big Ten title and top seeding in next week’s conference tournament.
The Wolverines (26-5, 15-5) will be seeded third in Chicago after falling to third place behind their rivals and No. 11 Purdue.
Winston was 1 of 8 before making five straight shots in the second half, including a 3-pointer to give Michigan State its first lead midway through the second half.
The Spartans then pulled away, winning easily in a game Michigan controlled for more than 20 minutes.
Winston made a layup with 5:58 left to cap a 25-4 run.
The Spartans trailed by six at halftime and by eight points early in the second half after Michigan’s Ignas Brazdeikis made a 3-pointer.
The Big Ten freshman of the year candidate fouled out with 20 points and Jordan Poole scored just five of his 15 points in the second half.
Michigan State’s Xavier Tillman scored 17 points and blocked five shots. Kenny Goins had nine points and 16 rebounds while fellow senior Matt McQuaid scored nine points and played well defensively in their final home game at the Breslin Center, where they kissed the school’s logo at midcourt to follow a tradition Shawn Respert started in 1995.
Michigan: Charles Matthews, who nearly 12 points a game, missed his third straight game. If the shooting guard can use the rest to be ready for the Big Ten and NCAA tournament, he can give the Wolverines a boost offensively.
Michigan State: Hall of Fame coach Tom Izzo won his ninth Big Ten regular season title despite missing two of his best players, Nick Ward and Joshua Langford, due to injuries. Ward might be able to play in the conference tournament and likely can contribute a little at least in the NCAA tournament.
Michigan: The third-seeded team in the Big Ten tournament will play the final game of the conference quarterfinals Friday night.
Michigan State: The first-seeded team will open the conference tournament quarterfinals on Friday afternoon.