CHAMPAIGN — James McCourt kicked a 39-yard field as time expired and Illinois pulled off the biggest upset of the college football season, knocking off No. 6 Wisconsin 24-23 on Saturday.

Tony Adams picked off a pass by Jack Coan for the Illini (3-5, 1-3 Big Ten), who were 30 {-point underdogs, at midfield with 2:33 remaining that led to the winning field goal. Dre Brown's tackle-breaking 13-yard run got Illinois to the Wisconsin 25 and then the Illini with 34 second left and then set up McCourt to attempt a game-winner. The junior kicker was down the middle with the field goal to give coach Lovie Smith the most significant victory of his four-year tenure in Champaign.

Wisconsin had not trailed this season and was looking to roll into a showdown with No. 3 Ohio State next week in Columbus. Instead, the Badgers (6-1, 4-1) blew a nine-point lead in the final 9:46 of the fourth quarter.

Illinois beat a ranked team for the first time since 2011 and knocked off a ranked Big Ten team for the first time since 2007, when the Illini beat No. 1 Ohio State in November on their way to a Rose Bowl appearance.

The last time Illinois beat a ranked Big Ten team at home was October 2007, a 31-26 victory against No. 5 Wisconsin.

Heisman Trophy contender Jonathan Taylor rushed 28 times for 132 yards and one touchdown for Wisconsin, but he also had a fumble in Illinois territory in the fourth quarter to help fuel the Illinois comeback.

Coan was 24 of 32 passing for 264 yards and a touchdown, but his one interception came at a crucial time.

He sailed a pass on third-and-5 that Adams grabbed to give the Illinois a short field against the No. 1 defense in the nation.

Illinois had cut Wisconsin's lead to 20-14 late in the third quarter on a 43-yard touchdown run by Reggie Corbin.

Wisconsin had opportunities to pad its lead, but settled for a field goal after a first-and-goal from the 3 and then Taylor fumbled at the Illinois 25.

After the fumble, the Illini ripped off a 75-yard touchdown drive, capped by Brandon Peters' 29-yard pass to Josh Imatorbhebhe to make it 23-21 with 5:53 left.