SAN FRANCISCO — Buster Posey took off from first on Pablo Sandoval's sixth-inning double with what looked like a good chance of scoring the tying run.
Instead, Arizona shortstop Cliff Pennington made the perfect throw home on a relay, and the first-place Diamondbacks held off a late San Francisco rally to beat All-Star Madison Bumgarner and the Giants 3-1 on Sunday and avoid a three-game sweep.
"It happens. That's the way it goes sometimes," Posey said. "They made a good relay and a good throw to the plate."
Posey got aboard on a leadoff walk in the sixth, and Sandoval followed with a double off the wall. Third-base coach Tim Flannery claimed responsibility for the loss for sending the reigning NL MVP.
"You never want anybody thrown out. I feel terrible," Flannery said. "I feel responsible for not getting Bum the win. It comes with the territory. With nobody out, that can't happen."
Paul Goldschmidt hit a sacrifice fly and a double against Bumgarner, Cody Ross added a late two-run single, and the first-place D-backs bounced back in the series finale.
Randall Delgado (2-3) won in his first career start at AT&T Park, and Goldschmidt's first-inning sac fly got things going against the inconsistent defending World Series champions.
"We couldn't figure him out until later in the game," manager Bruce Bochy said of Delgado.
A day after stranding 13 baserunners and going 2 for 12 with runners in scoring position, the D-backs did just enough against Bumgarner in the 10-game winner's first outing after the All-Star break.
Ross singled in the eighth as Arizona won for just the fourth time in 16 road games.
The Giants were denied their first sweep of Arizona at home since May 10-12, 2011.
"We had a chance to sweep the series but it's big to win the series, so we'll take that," Bumgarner said.
San Francisco won the first two games of the series, but the NL West-leading Diamondbacks (51-17) gained a game back to give themselves a 5 1/2-game cushion over the Giants and remain a half-game ahead of second-place Los Angeles.
Bumgarner, for one, wasn't pointing fingers at the emotional Flannery.
"I don't think anyone is blaming on him except himself," Bumgarner said. "He's a great third base coach and I'm thankful he's part of the team. He takes it personal but you are not going to be right all the time. They had to make two great throws,
and they did."
Bochy said Pennington played it well.
"It looked like Buster was going to make it but the shortstop came up throwing," Bochy said. "You hate to see that happen but give them credit for making the relay."
Goldschmidt, 1 for 9 in the first two games of the series, doubled to start the fourth and drew walks in the sixth and eighth innings. Delgado allowed three hits, struck out two and walked four in 5 2/3 innings.