Jeff Keppinger doubled in two runs in the fifth inning against his former team and the San Francisco Giants held on to defeat the visiting Houston Astros 2-1 on Friday.

Madison Bumgarner (8-12) gave up one run on five hits over 6 1/3 innings for the Giants, who remained three games behind Arizona in the National League West.

With closer Brian Wilson on the disabled list, Santiago Casilla worked a perfect ninth for his second save.

Astros starter J.A. Happ (4-15) gave up two runs - one earned - over six innings in his first start since being optioned to the minors three weeks ago.

Keppinger, who was traded to the Giants on July 19, doubled to deep center in the fifth after fouling off four two-strike pitches against Happ.

The Giants improved to 30-19 in one-run games and 52-2 when leading after eight innings. Nine of the Giants' last 11 games have been decided by two runs or less.