Peavy delayed Detroit's chance to move closer to the AL Central title, pitching the Chicago White Sox past the slumping Tigers 8-0 Friday night.
Detroit's lead was cut to one game by Minnesota, which beat Kansas City 10-7. Both teams have two games left.
The Tigers, who couldn't take advantage of an opportunity Thursday to win the division with a win over Minnesota, heard a smattering of boos during their series opener against the White Sox.
"For the last day or so, they've been disappointed," Detroit manager Jim Leyland said. "Most people when they're disappointed, they express their disappointment in the form of boos. There's nothing wrong with that."
The Tigers went into the final weekend with a two-game lead over Minnesota, but got off to a bad start when Scott Podsednik hit a leadoff home run.
Peavy (3-0) pitched eight scoreless innings and Carlos Quentin also homered. Out for three months because of an injured right ankle, Peavy gave up just two hits and showed the form he had as the 2007 NL Cy Young winner.
"I still don't feel 100 percent," Peavy insisted.
Edwin Jackson (13-9) gave up a career-high eight runs and seven hits over five-plus innings.
"The one thing you have to have when you pitch against a guy like Peavy, your pitcher has to pitch good," Leyland said. "[Jackson] just made way too many bad pitches in the middle of the plate."
If the Tigers fail to hold off Minnesota, they will become the first team in major league history to lead a division on May 10 and stay atop it until losing the title in the last week of a season.
Detroit still has an opportunity, though, to win the AL Central without any help from the last-place Royals. With a magic number of two, the Tigers can wrap up the division by beating the White Sox the next two days.
"We're just trying to win theses games," White Sox catcher A.J. Pierzynski said. "We don't have a vendetta or anything because it's Detroit or Minnesota."
"I know it's an important game," the 25-year-old Figaro said quietly on the eve of the third start in his career. "I'm not nervous. I'm a little bit excited."
Podsednik sent Jackson's third pitch into the right-field seats for just his sixth homer of the year and his first to lead off a game since 2004. Detroit had its best hitter, Miguel Cabrera, at the plate in the first with two on and one out and Peavy struck him out and got Aubrey Huff to fly out.
"We had a shot in the first inning, but we didn't do it and his ball was darting all over," Leyland said.
After Placido Polanco hit a one-out single against Peavy in the first, Detroit didn't get a base hit off him until Al Avila singled to lead off the eighth. The Tigers, among the AL's lowest-scoring teams, have been shut out six times this season.
"I've been puzzled all year why we haven't hit better," Leyland said. "It's simple -- we have to score runs. If we don't, we'll get beat."
Peavy had a sensational start even though he said his slider and offspeed pitchers weren't sharp, relying on fastballs low in the zone.
"I was able to get ground balls when I needed them," he said.
Jackson, who lately has not looked like the All-Star he was at midseason, let the game get out of reach in a five-run sixth.
"It's definitely one of those games you just try to forget about," Jackson said.
If the Tigers waste their lead, that won't be easy to do.
Peavy threw seven scoreless innings last week against Detroit and is 3-0 with a 1.35 ERA in three starts for the White Sox. ... Magglio Ordonez extended his hitting streak to 10 games. ... Pierzynski's 150th hit tied his own team record for hits by a catcher. ... Detroit's Gerald Laird matched a career high by throwing out a 39th runner attempting to steal, and extended his lead in that category in the majors.