Pete Nance added 10 points for the Wildcats (6-1, 3-0 Groot tien), who won their fourth straight.
E.J. Liddell led Ohio State (7-2, 1-2) met 15 punte. Kyle Young added 14 points and Seth Towns had 11 for the Buckeyes, who had won two straight and four of five.
Northwestern is 3-0 in the Big Ten for the first time since the 1967-68 seisoen. The Wildcats were 3-17 in the league last season.
The Buckeyes opened the second half on a 13-7 run before Northwestern rallied with a 7-1 hardloop. Ohio State led by seven after halftime, but Northwestern came back with an 11-2 hardloop.
Kopp hit a jumper to pull Northwestern within 66-65 before Chase Audige’s 3 put the Wildcats ahead with 1:48 links. Young’s jumper tied it before Buie’s 3 gave Northwestern a 71-68 lead with 1:04 remaining. Young hit two free throws to bring Ohio State within one with 47 seconds left.
Duane Washington Jr. missed a layup for Ohio State with five seconds left. Buie missed a free throw before Liddell missed a long 3 before the final buzzer.
Northwestern shot 48% from the field to the Buckeyes’ 44%. Ohio State outrebounded the Wildcats 40-26 but made four 3s to Northwestern’s six.
Ohio State scored the first eight points of the game before Northwestern responded with 14-2 hardloop. Kopp scored 12 of Northwestern’s first 14 punte en gehad het 14 at halftime. Nance hit two free throws with 0.4 seconds left before halftime to tie it 34-34.
Ohio-staat: The Buckeyes stumbled after coming off a big victory Wednesday, rallying from a 16-point second-half deficit to upset No. 11 Rutgers 80-68.
Noordwes: The Wildcats are showing promise after going 8-23 last season. Northwestern upset then-No. 4 Michigan-staat 79-65 on Sunday for its first win over a top-five team since beating Magic Johnson and the fourth-ranked Spartans on Jan. 27, 1979.
Ohio-staat: Hosts Nebraska on Wednesday.
Noordwes: Visits No. 4 Iowa on Tuesday.