Phoenix, AZ (SportsNetwork.com) - Jake Peavy pitched into the eighth inning and Brandon Crawford knocked in the go-ahead run in the seventh as San Francisco edged Arizona by a 2-1 count in the second of three between the clubs.

Peavy (6-4) scattered five hits and one run over 7 2/3 innings, striking out four. Sergio Romo got the final out of the eighth and Santiago Casilla closed the door in the ninth for his 16th save.

"I feel very blessed to feel healthy and go out there and be a contributing factor to a team that's fighting for our lives every day," Peavy said.

Buster Posey homered and Pablo Sandoval added two hits for the Giants, who halted a three-game slide and trail the Dodgers by three games in the NL West after Colorado bested Los Angeles earlier Tuesday.

"Up and down, soft and hard, it doesn't matter. He seems to get the bat on it," Arizona starting pitcher Josh Collmenter said of Posey.

Chris Owings tripled and scored his club's lone run on an RBI single from A.J. Pollock as the Diamondbacks had their three-game win streak snapped.

Collmenter (10-8) allowed two runs on seven hits over his eight-inning outing.

Arizona tied the score in the sixth, as Owings tripled and scored on a Pollock base hit, but San Francisco came right back in the seventh.

Singles by Hunter Pence and Travis Ishikawa to kick off the frame left runners at the corners and Crawford's fly to center gave the visitors a 2-1 edge.

Peavy left with two down in the eighth and runners on first and second thanks to a single by Ender Inciarte and plunking Owings, but Romo quelled the rally by getting Pollock to fly to right.

Casilla then retired the hosts in order to lock down the win.

Posey's one-out solo homer put the Giants on the board in the fourth.