Posey hit his first career walk-off home run leading off the bottom of the ninth inning to give the San Francisco Giants a 2-1 victory over the Los Angeles Dodgers on Metallica Night at AT&T Park.
Posey had two hits and drove in both runs for the Giants, who won their fourth straight.
"It was a good feeling," Posey said of his shot. "The game was already way too long for being 1-1. I was enjoying the moment, taking in all the excitement."
Posey hit a 3-2 pitch off Ronald Belisaro that landed about 15 rows up in the left-field bleachers. It was his first hit in eight at-bats against the Dodgers right-hander. Belisaro struck him out five times and walked him once.
"We don't hit too many of them, but they are coming at a great time," Giants manager Bruce Bochy said. "He's a guy you want up there. He ran a deep count and got a pitch he could handle."