The ninth-ranked Buckeyes took advantage of Wisconsin turnovers to steal a 17-0 first-quarter lead en route to a 30-17 victory at Madison, Wis., for their ninth straight victory.
If Ohio State beats or ties Michigan next week in Columbus, Ohio, the Buckeyes (9-2 and 7-0) will win the title outright and a berth in the Rose Bowl on Jan. 1.
Wisconsin, which beat Ohio State in four of the previous five meetings, is 3-8 and 2-5.
"In the past, it was hard to focus on the team we played just before Michigan," said backup quarterback Tom Tupa, who filled in for Jim Karsatos. "But the team did a pretty good job of keeping their minds on Wisconsin."
Karsatos, who has a recurring left shoulder injury, was taken out in the second quarter as a precaution.
Jim Hilles, the interim football coach at Wisconsin, said his team was too accommodating to the Buckeyes. Wisconsin had two turnovers in the first quarter, and Ohio State converted each into scores.
"You can't spot a team like Ohio State 17 points, then expect to come back and beat them," Hilles said.
Vince Workman scored on runs of 32 and 3 yards as he rolled up 172 yards in 29 carries for the Buckeyes.
Ohio State receiver Cris Carter had 7 receptions for 112 yards to become the Buckeyes' all-time leading receiver with 157 catches. Gary Williams had 154 catches in 1979-82.
Greenfield threw scoring passes of 39 yards to Curtis Duncan and 3 yards to George Jones, and Claudell Robertson ran 12 yards for a touchdown to give the Wildcats their first Big Ten victory of the season in seven tries. Northwestern is 3-7 overall. Michigan State is 3-4 and 5-5.
Lorenzo White, Michigan State's top rusher, reinjured his right ankle and left the game midway into the first quarter after gaining 18 yards in 7 carries.
Poholsky, who completed 15 of 21 passes for 259 yards, played in place of injured senior quarterback Mark Vlasic as Iowa improved to 7-3 overall and 4-3 in the Big Ten. Purdue is 2-8 and 1-6.
Illinois 21, Indiana 16--At Bloomington, Ind., Brian Menkhausen scored on a one-yard run midway through the fourth quarter for the Illini's winning touchdown in a Big Ten victory over the Hoosiers.
Illinois is 4-6 overall, 3-4 in the conference, and Indiana, hoping for a bowl bid, dropped to 6-4, 3-4.