Brandon Belt hit a game-ending single to left-center with one out in the ninth, Buster Posey tied it with a two-run homer in the eighth, and the San Francisco Giants rallied to beat the Arizona Diamondbacks 5-4 on Monday night for their seventh straight home victory.
Posey's drive to straightaway center was his second homer of the year and in two days.
Belt's first career walkoff hit came against Tony Sipp (1-1), who allowed a leadoff single to Andres Torres. Brandon Crawford sacrificed him to second.
Jose Mijares struck out two in the ninth before yielding Cliff Pennington's double. Closer Sergio Romo (1-1) relieved in a double switch as Belt entered at first base. Romo retired pinch-hitter Eric Hinske on a first-pitch grounder.
Belt delivered hours after manager Bruce Bochy and hitting coaches Hensley Meulens and Joe Lefebvre met with him during batting practice and urged the struggling first baseman to slow his body movements down. Joaquin Arias started in his place.