MLB: San Francisco 8, San Diego 7

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SAN DIEGO, Aug. 19 (UPI) -- Hunter Pence's RBI double in the ninth inning proved to be the winning run Saturday in the San Francisco Giants' 8-7 victory over San Diego.

Buster Posey delivered a one-out double in the top of the ninth and scored when Pence drove a pitch into the right-field gap, giving the Giants what seemed like an insurance run and an 8-5 lead.

But San Francisco ended up needing it when Jeremy Affeldt allowed run-scoring singles to Alexi Amarista and Chris Denorfia in the bottom of the frame.

Clay Hensley notched his third save when he struck out pinch-hitter Mark Kotsay to end the game and hand the Giants a series-clinching victory.

Jose Mijares (1-0) earned the victory.

Joaquin Arias went 3-for-5 with a solo homer and three RBI, while Posey finished 3-for-4 with a sacrifice fly for San Francisco, which retained a one-half-game lead over the Los Angeles Dodgers atop the National League West.

San Diego's Brad Brach (1-3) was the loser in relief of starter Eric Stults, who gave up five runs over six innings.

Chase Headley went 2-for-4 with a three-run homer for the Padres.