EAST LANSING, Mich. -- Tom Izzo was choked up as he walked off the court, and the emotional display had nothing to do with matching Bob Knight's record for the most wins by a men's basketball coach at a Big Ten school.
"We needed to win a game, and we needed to win a game the way we won," Izzo said.
The slumping Spartans (19-9, 10-7) had lost three straight and five of six. The dramatic victory over the Boilermakers was win No. 662 for Izzo, equaling Knight's total with the Hoosiers from 1972 to 2000.
Izzo took over Michigan State's program in 1995 and, after struggling early, he won the national championship in 2000 during one of eight Final Four appearances. He chose to stay at the school after having chances to coach elsewhere in college and the NBA.
"He could've went a lot of places, and he didn't," Purdue coach Matt Painter. "A lot people around here forget his first two seasons, but they stuck by him and he took off from there."
The Boilermakers (24-5, 13-5) had won three straight and nine of 10 overall.
"I still think they're the best team in the league, but we earned the win," Izzo said.
Purdue rallied from an 11-point deficit midway through the second half and pulled into a tie twice in the last minute.
The Boilermakers had two chances to extend the game after Walker's 3-pointer just beat the shot clock.
On the first attempt, Williams' pass from the far baseline went through Ivey's hands just past half court. After Michigan State failed to get the ball in play, there were .4 seconds put on the clock and Purdue could not take advantage with a pass in the frontcourt that was broken up by Malik Hall.
Michigan State made 6 of 10 3-pointers on its way to a 35-33 lead at the break.
The Spartans started strong in the second half, and led 57-46 with 9:36 left.
Julius Marble's two foul shots gave Michigan State a 65-63 lead with 51 seconds remaining, but Williams scored in the post with 30 seconds left.
Izzo called a timeout with 16 seconds left and Walker made the winning 3-pointer from deep on the left wing that he ranked as the best of his career.
"This is No. 1 - easily," the Northeastern transfer said.
Purdue: Edey had one of the best performances of his career, and the timing was good for his team because some of his teammates struggled offensively. He had not scored 20 points in nearly a month and he surpassed his previous career high of 24 points that he had Jan. 3 in a loss against Wisconsin.
Izzo said Edey, who was 10 of 15 from the field, was allowed to take a lot of shots by design.
"The game plan was to not give up the 3, and they went 1 for 9 from the 3," Izzo said.
Michigan State: Brown bounced back from a five-game slump. Brown averaged 3.9 points and was held scoreless twice while shooting 19% in the previous five games. He made a 3-pointer on the opening possession and finished 3 of 5 beyond the arc.
"Why did he need to hit those against us?" Painter said. "He was feeling good about himself."
Purdue: Closes the regular season Tuesday at No. 13 Wisconsin and at home against rival Indiana on Saturday.
Michigan State: Play rival Michigan on the road Tuesday, at No. 22 Ohio State on Thursday and Maryland at home next Sunday.