Buster Posey hit a two-run homer off new Arizona closer Addison Reed in the ninth inning and the San Francisco Giants rallied from four runs down to beat the Diamondbacks 9-8 on Monday night.
It was the season opener for San Francisco and the first true home game for the Diamondbacks, who started the season with two losses as the home team against the Los Angeles Dodgers in Australia.
Miguel Montero, who had three hits and reached base five times, homered to lead off the Arizona ninth and make it a one-run game.
Brandon Belt had three hits, including a solo home run, and singled ahead of Posey's homer.
Arizona scored four unearned runs off starter Madison Bumgarner in the fourth and led 7-3 after six. San Francisco got four runs with two outs in the seventh, with reliever Brad Ziegler walking in the tying run.
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