Giants 2, Diamondbacks 1: Buster Posey homered among his two hits and Jake Peavy pitched into the eighth inning as visiting San Francisco snapped its three-game losing streak.

Peavy (7-13) won his fourth consecutive start while holding Arizona to one run over 7 2/3 innings and Santiago Casilla worked a perfect ninth for his 16th save. Pablo Sandoval and Brandon Crawford had two hits apiece for wild card-leading San Francisco, which moved three games behind first-place Los Angeles in the National League West with 11 remaining.

Josh Collmenter (10-8) cruised through the first three frames before Posey belted a solo homer into the left-field seats with one out in the fourth. Collmenter allowed two runs on seven hits over eight innings for the Diamondbacks, who saw their three-game winning streak come to an end.

Arizona pulled even in the sixth as Chris Owings belted a one-out triple and scored on A.J. Pollock’s single past a diving Sandoval at third. The Giants opened the seventh with back-to-back singles by Hunter Pence and Travis Ishikawa before Brandon Crawford drove in the go-ahead run with a sacrifice fly to deep center.

Peavy, who owns a 1.13 ERA over his last seven starts, exited with two on and two out in the eighth and watched Sergio Romo retire Pollock to end the inning. Ender Inciarte had two hits for the Diamondbacks, who were held to five hits after scoring 24 runs during their three-game winning streak.

GAME NOTEBOOK: Posey is 11-for-18 with three homers and eight RBIs against Collmenter. … Diamondbacks LHP Andrew Chafin will start Wednesday’s series finale in place of RHP Randall Delgado, who is being moved to the bullpen. … San Francisco OF Juan Perez went 0-for-4 while starting in place of Angel Pagan, who was missed his second straight game due to back stiffness.