Mike Gesell scored a career-high 25 points and Iowa cruised past top-ranked Michigan State 83-70 on Tuesday night, handing the Spartans their first loss of the season.
Peter Jok had 19 points for the Hawkeyes (10-3, 1-0 Big Ten), which toppled a No. 1 team for the first time in 16 years.
Iowa never trailed in what turned out to be a surprisingly easy win over the Spartans (13-1, 0-1). The Hawkeyes led by as many as 19 points in snapping a nine-game losing streak against Michigan State.
Eron Harris scored 21 points to lead the Spartans. They were playing their second game without Valentine - their leader in scoring, rebounds and assists - and their first since Izzo's father Carl died Monday.
Iowa kept Michigan State off the scoreboard for nearly 6 minutes, and Dom Uhl's banked 3 put the Hawkeyes up 31-17 - despite having star Jarrod Uthoff on the bench with foul trouble - with just over 5 minutes left in the first half.
The Spartans trailed by double digits at halftime, this time 37-23, for the second straight game.
Consecutive 3s from Jok made it 58-39 with 11 minutes left, and Iowa cruised to its first win over a No. 1 team since beating Connecticut in former coach Steve Alford's debut in 1999.
Matt Costello had 17 points for Michigan State.