PHOENIX (AP) - Justin Upton homered on the first pitch he saw in the 10th inning and the Arizona Diamondbacks avoided a sweep at the hands of San Francisco with a 3-2 victory over the Giants on Thursday night.
Upton's opposite-field home run off Santiago Casilla (0-1) was his first career "walk-off" homer and the first home run given up by Casilla this season.
Ian Kennedy gave up only an unearned run on four hits and struck out 10 with one walk over eight innings to stake the Diamondbacks to a 2-1 lead. But Pat Burrell's RBI sacrifice fly in the ninth tied it as J.J. Putz, struggling lately after an outstanding start to the season, blew his third save in 21 opportunities.
The Diamondbacks snapped San Francisco's five-game winning streak against them.
Chris Young homered for Arizona for the second night in a row and David Hernandez (3-2) pitched a scoreless 10th to get the victory.
The Diamondbacks pulled within 1 1/2 games of first-place San Francisco in the NL West.
Upton also had a single and double. He had two winning singles in his career, but never a home run until Thursday night.
Putz, charged with two runs in Arizona's 5-2 loss on Wednesday night, has been scored upon in four of his last seven appearances after setting a franchise record by starting the season with 16 straight saves.
San Francisco started the ninth with Pablo Sandoval's single past second baseman Kelly Johnson, then Aubrey Huff bounced one over the head of first baseman Juan Miranda to put runners at first and third with no outs. Putz struck out Cody Ross but Burrell lofted one to left to bring in the tying run before Brandon Crawford flew out to left to end the inning.
After Hernandez retired the side for Arizona, Casilla, who had allowed just two runs in 8 2-3 innings of work this season, got leadoff batter Stephen Drew to ground out. Upton, though, wasted no time, bringing the night to an end with his 12th home run of the season.
Upton, who also doubled in the eighth, led off the fourth with a single, then on a 1-2 pitch, Young pulled one down the left-field line into the Arizona bullpen, his 14th home run to give the Diamondbacks a 2-0 lead. It was the first time Arizona was ahead in the series.
San Francisco responded with an unearned run in the fifth. Ross and Nate Schierholtz started the inning with singles. Brandon Crawford fouled out to the catcher, then in a 10-pitch at bat, Eli Whiteside struck out swinging. San Francisco sent both runners on the play, and catcher Miguel Montero threw wild to third, allowing Ross to score and Schierholtz to advance to third. Vogelsong struck out to end the inning, with the Diamondbacks still on top, 2-1.
The Giants got the first two runners on base with no outs again in the seventh when Aubrey Huff singled and Ross drew the only walk off Kennedy of the night. But Schierholtz flew out to left, Crawford bounced out to first and Whiteside flew out to center.
Giants starter Ryan Vogelsong allowed two runs on six hits in six innings, striking out six and walking one.
NOTES: Giants OF Darren Ford (sprained left ankle) began a rehab assignment Thursday night with Triple-A Fresno. ... Arizona entered the game leading the NL and second in the majors, behind Boston, in extra-base hits. ... The game was the ninth of 18 scheduled between the Giants and Diamondbacks this season.