Buster Posey hit a two-run homer and Freddy Sanchez drove in three runs as the visiting San Francisco Giants won their fourth straight, 5-3 over the Arizona Diamondbacks on Saturday.

Aaron Rowand went 3-for-4 with two runs scored and Mark DeRosa had two hits for the Giants, who have won seven of nine.

Barry Zito started for San Francisco, but left in the second inning because of a right foot sprain suffered while making a lunging catch. Guillermo Mota came on in relief and worked 4 1/3 innings - the longest outing of his 13-year career.

Mota (1-0) allowed one run, three hits and struck out four in 50 pitches.

Posey’s blast off Joe Saunders (0-2) in the first inning put the Giants on top, but Arizona would take the lead with two runs in the second and one more in the fourth.

San Francisco jumped on Saunders again in the sixth, pushing a run across on Sanchez’s double. The lefthander loaded the bases in the seventh before being removed in favor of Sam Demel, who yielded Sanchez’s two-run single to left.

Jeremy Affeldt and Sergio Romo got the ball to closer Brian Wilson, who worked the ninth for his fourth save.