(Photo credit: Joe Camporeale-Imagn Images)

James McCann hit a two-run homer in a six-run sixth inning, Zac Gallen threw six strong innings and the Arizona Diamondbacks beat San Francisco 8-1 in Phoenix on Monday to leapfrog the Giants in the National League wild-card race.

McCann homered for the second straight game and Ildemaro Vargas had a two-run single to ignite the sixth-inning rally against Matt Gage (0-1) and two other Giants relievers.

Geraldo Perdomo singled, doubled, tripled, walked twice and drove in two runs for the D-backs. His triple capped the big sixth, and he doubled home the final run in the eighth.

Gallen (12-14) gave up two hits and one run, Casey Schmitt's homer in the third. He struck out six and walked one for his fifth victory in his past seven decisions.

The D-backs (76-75) won their fourth game in the past five and closed within 1 1/2 games of the idle New York Mets (77-73) for third NL wild-card spot. The Mets open a three-game home series against the San Diego Padres on Tuesday.

The Giants (75-75) lost their third straight and dropped into a tie with the Cincinnati Reds (75-75), two games back of New York.

Corbin Carroll doubled to lead off the sixth, knocking Gage out of the game. Joel Peguero entered and walked two to load the bases before Vargas singled to right to score two, though he was thrown out at second on the play.

The Giants made another pitching change, going with Joey Lucchesi, and pinch hitter Jordan Lawlar added an RBI double before McCann homered. Jake McCarthy reached on an error and scored on Perdomo's triple.

McCann wore jersey No. 21 instead of his usual No. 8 to honor Roberto Clemente, who is celebrated every season on Sept. 15.

Giants rookie starter Kai-Wei Teng kept his team in the game, giving up two hits and an unearned run in four innings. He struck out five and walked one in his seventh appearance and sixth start.

San Francisco designated hitter Bryce Eldridge, promoted before the game from Triple-A Sacramento, went 0-for-3 with a strikeout in his major league debut.

The D-backs took a 1-0 lead in the first with help from Teng, who walked Perdomo and hit Ketel Marte with a pitch before striking out Carroll and Gabriel Moreno. Perdomo took third on a passed ball and scored on Teng's errant pickoff throw to first.

Schmitt's 418-foot homer to left-center tied it with one out in the third. Gallen has given up a career-high 29 homers this season, second most in the NL.

--Field Level Media