The Padres (72-74) have lost five of six but still hold a 5½-game lead over San Francisco and Los Angeles. This is the latest in a season that a team has led a division with a losing record. The Padres, who swept the Nationals in Washington Aug. 5-7, have 16 games left.
Cristian Guzman tripled, doubled and drove in three runs for the Nationals, who won their fourth straight. They remained 2½ games behind Houston in the wild-card chase, with Philadelphia and Florida also in front of them.
The only encouragement the Padres got out of the game was that Peavy (12-7) is healthy. He missed a scheduled start last Saturday after feeling a sharp pain in the back of his right shoulder in his previous two starts.
"I felt good tonight," Peavy said. "I just made some bad pitches and cost us the game. I hate that we lost, but we've got a couple more starts to get back to full strength and hopefully we can push this thing to the playoffs and I'll throw good for that."
Said Washington manager Frank Robinson: "Peavy wasn't at the top of his game. That wasn't Peavy out there, but we'll take it."
Patterson (9-5) struck out six, walked none and allowed only one baserunner after the second inning. He retired the last 14 batters he faced. His other complete game came Aug. 4, a 7-0 win against Los Angeles.
"I was a little rusty early in the game," Patterson said. "But I got my focus and location. Once we scored the runs, I felt great and got back in the groove."
Robinson called it "an outstanding performance on his part. After the first inning, he was really in full control."
San Diego took a 1-0 lead on Ramon Hernandez's homer with two outs in the first.
"Once he gave up the home run, we really didn't create any opportunities there," Padres manager Bruce Bochy said. "He was on top of his game. Sometimes you run into a well-pitched game, and I think that was the case more than anything tonight."
San Diego's offense struggled yet again. On Wednesday, the Padres rallied to win 5-4 in 10 innings at San Francisco.
"We're disappointed we haven't been more consistent and put together a winning streak here," Bochy said.
Peavy looked strong early, retiring 10 batters in a row before Nick Johnson singled leading off the fifth.
Johnson was thrown out trying to steal second and Peavy struck out Preston Wilson, but the right-hander then allowed three straight runners and fell behind 2-1. Vinny Castilla singled to center and Gary Bennett walked before Guzman, who came in hitting .204, doubled to center.
Peavy loaded the bases with no outs in the sixth, allowing singles to Brad Wilkerson and Jose Vidro, and hitting Jose Guillen with a pitch. Johnson's grounder to first forced Wilkerson at home for the first out. Wilson hit a high bouncer off the plate to third for an RBI infield single, and a second run scored on Sean Burroughs' throwing error, making it 4-1.
Peavy lasted six innings, allowing four runs, three earned, on seven hits. He struck out six and walked one.
Guzman hit an RBI triple off Scott Cassidy in the ninth.
Hernandez homered to left on a 3-1 pitch from Patterson, his ninth.
- It was the 20th time in 28 starts that Patterson allowed two or fewer runs.
- Burroughs made his first start since being recalled from Triple-A Portland on Aug. 31. He spent 5½ weeks in the minors working on his batting stroke. On Wednesday, Burroughs hit a tying two-run double with two outs in the ninth off San Francisco's Armando Benitez, and the Padres won it 5-4 in the 10th.