EAST LANSING, Mich. -- His shoulder and his ankle wouldn't stop hurting, but that pain was nothing compared to the thought of his team's Rose Bowl chances slipping away.
So Kirk Cousins played on, leading Michigan State (No. 12 BCS, No. 11 AP) on a desperate fourth-quarter rally that kept the Spartans atop the Big Ten for another week.
Cousins lunged into the end zone from 3 yards out with 4:32 remaining to give Michigan State a dramatic 35-31 victory over Purdue on Saturday. The Spartans trailed 28-13 after three quarters and 31-20 midway through the fourth, but the Boilermakers couldn't hold off the hobbled Cousins.
"I've been battling a sprained shoulder and a sprained ankle for three or four weeks," the Michigan State quarterback said. "They're not going to heal if you keep playing on them, but you can keep playing if you can take the pain."
The Spartans (10-1, 6-1 Big Ten) remain tied for first in the Big Ten with Wisconsin and Ohio State. Michigan State would win a two-way tie with Wisconsin, but if all three teams win next week, the tie would be broken by the BCS standings, which have the Spartans last among the trio.
Michigan State was favored by around three touchdowns for its home finale against Purdue, which has now lost five straight and cannot become bowl eligible. But the Boilermakers (4-7, 2-5) had the Spartans on the ropes in the fourth quarter before Rob Henry's deep pass was intercepted by Chris L. Rucker at the Purdue 40. Rucker returned it to the 20, and Cousins threw a 5-yard touchdown pass to B.J. Cunningham to make it 28-20.
After a long kickoff return, Purdue's Carson Wiggs made it 31-20 with a 52-yard field goal, but Cousins threw a 9-yard touchdown pass to Mark Dell with 6:54 remaining, and a 2-point conversion made it 31-28.
With momentum already shifting, Denicos Allen came charging in from the right side and blocked a punt, giving Michigan State the ball inside the 5 and setting up Cousins' touchdown.
"It hit me in the stomach," Allen said. "My stomach was kind of sore afterward."
Cousins' winning touchdown run was upheld by replay after the ball came free, but Michigan State appeared to recover it in the end zone anyway.
Cousins missed a series in the first half after appearing to hurt his non-throwing shoulder. Despite that and his ankle problem, he went 28 of 37 for 276 yards and three touchdowns.
"I was very close to pulling myself out of the game," Cousins said. "I got a shot for the shoulder and a shot for the ankle at halftime. I have a footwork problem. I can't plant and pivot without excruciating pain."
After Cousins put the Spartans ahead, Purdue drove to the Michigan State 20, but on fourth down, Henry threw an interception while under pressure from All-America linebacker Greg Jones.
"It's kind of unbelievable," Purdue defensive lineman Ryan Kerrigan said. "You start off 4-2 on the year and you're not going to postseason play. It's pretty disheartening, especially to be a senior and have that happen."
Michigan State rallied from an 11-point fourth-quarter deficit to beat Purdue 40-37 last season.
There was even more at stake this time. The Spartans have now won 10 games for only the third time, and this senior class has won a school-record 32. Michigan State plays its regular-season finale at Penn State next weekend.
"We know we're going to play in a major bowl," coach Mark Dantonio said. "If we win, regardless of what goes on, we've got a chance to be at least co-champions. That's special. I'm so happy for our seniors. It's very emotional for them."
Michigan State took a 7-0 lead on a 24-yard touchdown pass from Cousins to Dell, but nothing came easy after that. Purdue needed less than a minute to answer. Keith Carlos ran up the middle, eluded safety Trenton Robinson and then had nothing but open field in front of him for an 80-yard touchdown.
Ricardo Allen then gave the Boilermakers the lead, stepping in front of one of Cousins' passes and returning the interception 35 yards for a touchdown. Cousins would finish the first half 12 of 13 for 105 yards, but his only miss was a costly one.
The Spartans scored early in the second quarter on a 19-yard run by Edwin Baker, who surpassed 1,000 yards rushing on the season Saturday. However, the normally reliable Dan Conroy kicked the extra point off the upright to leave Michigan State still a point behind.
With the second quarter nearing an end, Purdue went on its first sustained drive of the day, going 85 yards in 14 plays. Henry threw an 8-yard touchdown pass on third down to Antavian Edison with 9 seconds left to make it 21-13.
Purdue made it 28-13 on Henry's 12-yard scoring pass to Cortez Smith in the third quarter.