EAST LANSING, Mich. — Javon Ringer scored two touchdowns and No. 18 Michigan State used a dominating defense today to stay alive in the Big Ten title chase with a 21-7 victory over Purdue.

The Spartans (9-2, 6-1 Big Ten), who are off next week, will rest up for a Nov. 22 showdown at No. 3 Penn State, with at least a share of the conference title on the line.

The Spartans last won a share of the Big Ten crown in 1990.

Purdue (3-7, 1-5) was officially eliminated from bowl contention in coach Joe Tiller's final season.

Ringer, one of 16 Spartans playing their final home game Saturday, had 121 yards on 32 carries. He entered the game ranked second in the nation at 142.7 yards per game. He is the second-leading career rusher in Michigan State history, trailing only Lorenzo White.

Ringer gave Michigan State a 7-0 lead with a fourth-down, 1-yard touchdown run on the Spartans' opening possession. His 1-yard TD run early in the second half gave Michigan State a 21-0 lead.

With just 9 seconds left in the first half, Michigan State defensive back Johnny Adams stepped in front of a Justin Siller pass and returned the interception 40 yards to give the Spartans a 14-0 halftime lead.

Purdue, hampered by turnovers all season, never recovered.

Siller started his second consecutive game in place of injured senior Curtis Painter. Siller was shaken up in the middle of the third quarter and replaced by Chris Bennett, but returned to the lineup later in the quarter.

Painter hurt his throwing shoulder Oct. 25 against Minnesota.

The Boilermakers couldn't generate much offense, particularly when it mattered most.

Purdue avoided a shutout by scoring with less than 1 minute to play on Siller's 1-yard touchdown run.

Purdue generated only 191 yards of total offense. Siller was 13-of-30 for 83 yards. Kory Sheets had 93 rushing yards on 22 carries.

Michigan State had 300 yards of offense. Quarterback Brian Hoyer was 10-of-22 for 154 yards with two interceptions.

Michigan State gave the Boilermakers chances to stay in the game by missing out on several scoring opportunities, particularly in the first half.

Late in the second quarter, an illegal procedure penalty left kicker Brett Swenson with a 44-yard field goal attempt into a howling November wind. The kick was on target but fell short in a powerful gust.

One Spartans drive ended with an Ashton Leggett fumble inside the Purdue 25. Another ended when Purdue's Torri Williams intercepted a Brian Hoyer pass at the Purdue 27.

Another second quarter drive ended when Ringer was stopped on a 4th-and-1 run at the Purdue 10.

But the Boilermakers couldn't capitalize.

The Boilermakers have a 19-game winless streak against teams ranked in the Top 25.

Purdue had won seven of the last nine meetings in the series, including two straight in East Lansing, before Saturday's loss.