Peavy struck out seven in four dominant innings, combining with three other pitchers for a two-hitter and the White Sox beat the Washington Nationals 3-0 Saturday.
"I had good stuff, no doubt about it," Peavy said. "But I've had that stuff in a couple of my starts. I just felt good today. When you feel good you're going to go out there and (perform well)."
Washington, which lost for just the second time in 14 games, was on the verge of hiring Davey Johnson as its new manager. General manager Mike Rizzo confirmed after that game that Johnson has agreed to terms but there are still contract details to be worked out before an announcement can be made.
Peavy (4-1), who gave up one hit, combined with starter John Danks, Brian Bruney and closer Sergio Santos to snap Washington's five-game winning streak. White Sox pitchers also combined for 13 strikeouts.
Danks left the game in the second inning with a strained right oblique, forcing both teams to adjust.
"Usually it's the starter (you prepare for) and for (Peavy) to come in and throw the way he did, it was definitely the Peavy from the Padres that I remember," Washington's Jerry Hairston Jr. said. "The velocity was really good, the pitches get in on you and made good pitches."
After a five-hour, 14-inning game that lasted until early Saturday morning, both teams had to deal with a quick turnaround and tired bullpens. Washington used eight pitchers on Friday and Chicago seven.
"I thought we got a break when Danks left the game," Nationals interim manager John McLaren said. "I thought we were going to hit their bullpen. Bruney stepped up to the plate and Peavy was unreal. I've seen Peavy a lot. He had some pitches that were unhittable."
Since Peavy had never been used in relief, he wasn't part of Washington's pregame video session for its hitters.
Bruney gave up a hit in 2 1/3 innings, and Santos followed Peavy by getting the last three outs for his 15th save.
"In all the games that I've been managing in my career, this is one I'm not going to forget," Guillen said. "The way the team stuck together when Danks went down, everyone knew how struggling we were in the pen, we could have used a couple of guys.
"All of a sudden three guys come up and say 'I'm ready to go if you need me.' That's class act. As a team, I hope this thing picks up to the next level and start playing better."
Peavy, who threw 104 pitches in his last start on Wednesday, made 55 pitches in his first appearance out of the bullpen after 238 career starts.
"I came in, played catch and told them I felt good," he said. "I told them I could throw two or three innings if need be. Obviously losing John we needed it to happen and it went well."
Chicago native and former Cub Tom Gorzelanny (2-6) matched his longest outing of the season with seven innings, allowing one run and seven hits while striking out eight.
"Going 14 innings and using every guy out there, you kind of realize that today was a big day," Gorzelanny said. "I had to go out there and give everything I had to try to get as far as I could this game."
The Nationals fell to 1-1 under McLaren after Jim Riggleman shockingly resigned on Thursday because of a contract dispute. McLaren will manage Washington's series finale on Sunday in Chicago, and Johnson is expected to take over on Monday when the Nationals start a series in Los Angeles.
"Gorzelanny really did a great job for us," McLaren said.. "The way it looked in the first inning, I wasn't sure if we could get more than five or maybe six (innings) at the most, but he did us a great service. I appreciated the way he stepped up."
The White Sox, who have won 17 straight interleague series, have won 18 of their last 23 games against the National League. While Danks won't know until Sunday how long his injury will keep him out, he was grateful for the performance of his teammates after he left Saturday's game.
"Jake did a great job, especially coming in with no notice like that," Danks said. "Bruney did great. Bruney has had to throw a lot lately and both those guys did a great job picking me up and picking up the bullpen. The bullpen needed some guys to pick it up and fortunately those guys stepped it up."
Danny Espinosa's stolen base in the second inning extended the streak of successful steals against the White Sox to 21 straight. However, Roger Bernadina was thrown out by Castro in the third, breaking the streak. Replays showed the throw was probably late. ... The Nationals are 7-4 in interleague this season after going 5-13 last season. ... Ryan Zimmerman struck out in each of his first three at-bats and is just one for his last 20 dating back to June 21. ... Peavy's strikeouts were the most by a White Sox reliever since Brandon McCarthy struck out eight in 5 2/3 relief innings against the Angels on Sept. 11, 2005. Chicago's Adam Dunn struck out in his first three at-bats against Gorzelanny, giving him 96 on the season, most in the American League, and falling to 1 for 52 against left-handes.