PHOENIX -- One day after battling the flu, Adrian Gonzalez didn't need a note from his doctor to return to the San Diego Padres' lineup.
"He was a 'go' from the time that he walked into the clubhouse, poked his head in here and poked his thumb in the air," manager Bud Black said.
David Eckstein added three hits and an RBI as the Padres took two of three in a wild series between NL West rivals.
San Diego rallied from a six-run deficit to win the opener, then nearly climbed out of a six-run hole in the second game.
On Wednesday night, San Diego opened a 5-0 lead behind Jake Peavy (5-5), then watched Arizona pull within 5-4 before putting the game away with three runs in the eighth inning, taking advantage of four walks and two errors.
The Diamondbacks cut the deficit to 8-5 with two outs in the ninth, forcing Black to call on ace closer Heath Bell, who got the final out for his major league-leading 14th save in 14 chances.
"That's how we play in this division," said Gonzalez, who also singled and drove in three runs. "We play each other tough. There are no easy wins."
San Diego CEO Jeff Moorad, a former Diamondbacks executive, dropped in on Black's postgame interview.
"Just keep winning series," Moorad said, grasping his manager's hand.
"You got it, brother," Black said.
The Diamondbacks just keep losing series -- especially at home, where they have dropped seven of nine series, including all three under new manager A.J. Hinch. The Diamondbacks fell 12½ games behind the NL West-leading Los Angeles Dodgers, the most they have trailed in the standings since finishing 42 games out in 2004.
Arizona's only victory in this series came on Tuesday night, when Gonzalez was scratched from the starting lineup with the flu, although he made a late pinch-hitting appearance.
The lefty slugger appeared to be back at full strength Wednesday night. In his first at-bat, Gonzalez drove a 2-1 pitch from Billy Buckner (1-1) 10 rows into the seats in left to give the Padres a 2-0 lead.
"I gave him a good pitch to hit, knowing he's the one guy I don't want to hurt me," Buckner said.
That looked to be enough support for Peavy, who cruised through the first five innings, allowing only two singles, both by Justin Upton. But the Diamondbacks ambushed Peavy in the sixth.
After Upton hit a two-run triple and scored on Stephen Drew's single, Peavy got out of the inning with a 5-3 lead. But he was gone one out into the seventh after singles by Ryan Roberts and Augie Ojeda.
Luke Gregerson gave up a sacrifice fly to Gerardo Parra to whittle the Diamondbacks' deficit to 5-4.
Peavy allowed four runs and a season-high eight hits in 6 1/3 innings, walking one and striking out five.
Peavy said he was bothered throughout the game by a strained right ankle, which affected his delivery as he pushed off the rubber.
"I didn't really have nothing from the get-go," he said.
Peavy said he didn't think the ankle would keep him from making his next start.
The Padres got three runs in the eighth as the Diamondbacks imploded, with Leo Rosales walking four, one intentionally. Rosales walked in a run and let another run score when he threw Scott Hairston's bunt down the right field line.
"Certainly the free ones are the toughest ones," Hinch said.
RHP Chad Gaudin will start Sunday for the Padres at Colorado. ... Arizona 3B Mark Reynolds struck out three times, pushing his league-leading total to 64.