EVANSTON, Ill. -- Tom Izzo didn't want to dampen what he called a good win.

But the Michigan State coach was still irked with a collection of lapses on Thursday despite a 76-45 Big Ten victory over Northwestern at Welsh-Ryan Arena.

"You cannot foul like we did, you cannot miss shot clock things like we did and you cannot turn the ball over like we did," Izzo said. "That's inexcusable. That's completely a lack of focus."

The No. 12 Spartans (18-4, 5-4) had 21 fouls, 15 turnovers and frequently pushed the shot clock to the limit.

But what they did right still outweighed any concerns.

"It was a game where we did enough good things and had enough people step up," said Izzo. "You make a shot and it takes away all evils. And we made a lot of shots."

Guard Denzel Valentine scored 19 points while freshman guard Matt McQuaid added 17.

The pair combined for 10 3-point field goals as the Spartans collectively hit 16-of-26 (61.5 percent) from the arc on the way to their second straight victory. Michigan State was 28-of-55 (50.9 percent) overall for the game.

"They got 26 open threes and made 16 and we got 23 open ones and made four," said Northwestern coach Chris Collins. "That's minus-36. Do the math, it's not brain surgery."

Guard Bryant McIntosh scored 14 points and forward Aaron Falzon added 11 for the poor-shooting Wildcats (15-7, 3-6).

Northwestern shot a season-low 20.7 percent (12-of-58) from the field for the game as a losing streak reached four, including three straight to ranked teams.

"When you can't put the ball in the basket you're not going to win against really good teams," Collins said. "

McQuaid scored 14 points in the second half while forward Deyonta Davis pulled down a game-high 11 rebounds and added six books as the Spartans claimed a 42-33 edge on the boards.

Michigan State, which has won seven straight in the series, led by 12 at halftime and opened 28-point lead at 64-36 on guard Bryn Forbes 3 pointer with 6:19 to play.

The Spartans scored the final 12 points.

"I thought we played awfully well defensively and then we made shots," Izzo said. "The first half we were sloppy with the ball but yet got a lead. Second half I thought we executed a little better. That's a really tough zone they play but I thought our defense was as tough as it needed to be."

The Michigan State win came on the heels of Saturday's 72-71 home victory over No. 8 Maryland which snapped a three-game losing streak.

The Spartans opened with seven unanswered points and hit 8 of 11 3-point attempts in the first half. The Spartans never trailed and led by as many as 15 points en route to a 36-24 halftime lead.

Valentine collected 14 first-half points, hitting four 3-pointers.

Northwestern hit only one of nine field-goal attempts to open the game and went 7-for-31 in the first half. McIntosh had 10 first-half points, and the Wildcats were 3 for 14 on 3-point attempts before the break.

"I feel badly for our guys because our effort level was tremendous," said Collins. "This game had nothing to do with effort, it had nothing to do with preparation (or) one team playing harder than another team. It was one team shot the crap out of it and one team couldn't make anything."

NOTES: Spartan G Denzel Valentine was averaging 22 points during his previous three games, four above his season average. ... Michigan State coach Tom Izzo earned his 513th career win, the second-best total for a coach at a Big Ten school. He broke a tie with former Purdue coach Gene Keady. ... The Spartans host Rutgers on Sunday, while Northwestern plays its fourth consecutive nationally ranked foe when it travels to No. 3 Iowa. ... The Wildcats fell to 0-5 against ranked teams. ... Northwestern sophomore G Bryant McIntosh and Illinois' Malcolm Hill are the only Big Ten players with multiple 30-point games. Both had two through midweek.