EVANSTON, Ill. (AP) -- Michigan State coach Tom Izzo fretted during practice that some of his younger players would have a difficult time adjusting to the tempo and unique style of Northwestern's offense.
Stopping an offense predicated on back-door cuts, picks and late-in-the-clock 3-pointers is hard to emulate in a non-game situation. As it turned out, Izzo had a reason to worry.
The No. 6 Spartans couldn't contain the Wildcats in the second half Saturday and had trouble making shots of their own as they watched their 15-game winning streak end in an 81-74 loss.
"We knew this was going to be a tough game for us with the youth that we have. We are not surprised, of course we don't usually get hit with the backcuts, but we are not surprised," Spartans forward Draymond Green said.
"We have freshmen and they have to understand that the way you guard other people you can't do that against Northwestern. It's not all their fault, we still have to a better job of helping them, but we will be fine."
Keith Appling had 17 points for the Spartans (15-3, 4-1) and Green had another strong game with 14 points and 14 rebounds.
The Spartans shot 65 percent in the first half and still trailed by two. In the second, they made just 34 percent.
"We didn't lose that game on the offensive end, we lost it on the defensive end," Izzo said. "We're not allowed to give up 81 points. It's ridiculous."
Northwestern shot 54 percent in the second half, finishing right at 50 against a team that was allowing just 37 percent all season. Teams had been averaging just 59.6 points against the Spartans through the first 17 games.
What really hurt Michigan State was the play of backup center Davide Curletti, who made his first start of the season and second of his career. Curletti had a season-high 17 points and six rebounds and his hustle helped the Wildcats pull of an important victory.
Northwestern fans stormed the court to celebrate. The Wildcats needed the win badly after a two-point overtime loss at Michigan three days earlier and a one-point setback against Illinois in their previous home game.
"Curletti was the difference in the game, if you ask me," said Izzo, who fell to 26-4 against the Wildcats in his career. "I thought he played extremely well and outplayed our centers and that's something we've been pretty solid on lately."
John Shurna had 22 points, 13 in the second half, and Drew Crawford had 20 for the Wildcats (12-5, 2-3).
Michigan State (15-3, 4-1) lost for the first time since it was beaten by Duke at Madison Square Garden on Nov. 15.
"The main thing was stopping them in transition because they have so many fast guards," said Crawford, who has been battling the flu. "Once we were able to stop them in transition, we're confident in our zone in the half court and we were kind of able to slow them down a bit, which really helped us out."
After such a torrid shooting first half, the Spartans missed 12 of their first 15 field goal attempts in the second. Shurna broke free for a layup and minutes later had a dunk as Northwestern increased the lead to 12 with 8:32 left.
State rallied with a 7-0 run started by Travis Trice's 3-pointer and cut the lead to 69-64 with 5:32 left. But Dave Sobolewski hit two free throws and Shurna made another 3-pointer from the top of the key and the lead was back to 10.
Izzo, still two wins shy of his 400th career victory, looked back at the first half when the Spartans had several leads -- they were ahead by as many as nine -- and a couple of missed opportunities when Northwestern wrestled rebounds away and then scored. On one of them, Curletti converted a three-point play.
"Probably the biggest thing was hustle plays. We had rebounds they took from us and scored three different times," Izzo said.
"They deserved to win and we didn't."
