Senior guard Cassius Winston scored 21 to lead No. 15 Michigan State to a 77-72 victory over Northwestern on Wednesday in Evanston, Ill.The victory means Michigan State (8-3, 2-0 Big Ten) sits alone in first place as the only unbeaten team in conference play as 12 teams sit at 1-1 through the first two games.Junior Xavier Tillman added 15 points and 10 rebounds for the Spartans while sophomore Gabe Brown chipped in 11 points and 10 rebounds to help Michigan State overcome 16 turnovers that led to 24 Northwestern points.Freshman Boo Buie scored 26 for Northwestern (5-5, 0-2), which made a late run and pulled within four in the final two minutes. Sophomore Pete Nance added 14 for the Wildcats.Winston was in rhythm early, hitting his first two 3-pointers of the game as Michigan State opened a quick 10-point lead. However, the Spartans missed their next six shots and turned the ball over three times to allow Northwestern to stay in the game.The turnovers crept in again later in the half as three more mishaps by the Spartans allowed the Wildcats to pull within 23-20 with eight minutes left in the half. Michigan State followed with a 9-0 run to take a 32-20 lead with just more than five minutes to play.