DENVER (AP) — Hector Sanchez hit two of San Francisco’s six homers, including a grand slam in the 11th inning Wednesday that gave the Giants a wild 12-10 victory over the Colorado Rockies.

With the Giants on the verge of being swept in a three-game series at Coors Field for the first time in 12 years, Sanchez drove a fastball from Chad Bettis (0-1) into the bushes behind center field. The backup catcher also hit a solo homer in the eighth.

Michael Morse also hit two homers — a solo shot in the second and a three-run homer the following inning — as two Giants hit multiple homers in the same game for the first time since May 25, 2005. Brandon Hicks and Brandon Belt also went deep as the Giants rallied from a 5-1, second-inning deficit.

Jean Machi (4-0) pitched a perfect 10th. Sergio Romo struggled in a non-save situation, surrendering a two-run homer to Justin Morneau but retiring Brandon Barnes on a game-ending 5-4-3 double play.

Hunter Pence led off the 11th with a single and Belt followed with a walk. After a sacrifice, Joaquin Arias was intentionally walked to get to Sanchez, who delivered his first career slam.

Sanchez finished with a career-high five RBIs.

He sent the first pitch from reliever Matt Belisle into the second deck to give the Giants an 8-7 lead in the eighth. But the Rockies tied it n the bottom half when D.J. LeMahieu singled and was bunted over to second. He went to third on a balk by Santiago Casilla and scored on Blackmon’s sharp grounder to Hicks, who couldn’t field it cleanly to make a play at home.

Matt Cain allowed seven runs, 10 hits and three walks in six innings and is 0-3 with a 4.35 ERA in five starts.

Charlie Blackmon finished 2 for 5 with a homer and four runs — lowering his batting average to .410. Troy Tulowitzki added a two-run homer and Nolan Arenado extended his hitting streak to 14 games with an RBI double in the seventh.

Belt’s two-run homer in the seventh gave the Giants a 7-6 lead and came off Rex Brothers. The hard-throwing lefty surrendered a game-ending, 10th-inning homer to Brandon Crawford on April 13.

Arenado tied the game with an RBI double off Cain. With two on and no outs, reliever Jeremy Affeldt was summoned into the game and got the Giants out of the predicament.

Giants manager Bruce Bochy tinkered with his starting lineup, resting catcher Buster Posey and outfielder Angel Pagan, who been bothered by knee soreness. Pagan entered as a pinch hitter in the eighth and grounded out. Posey was intentionally walked in the 10th.

Bochy said Pagan will have his knee checked out Thursday in San Francisco.

NOTES: Bochy was ejected in the fourth inning by plate umpire Chris Conroy, Bochy’s first ejection this season. ... The Giants and Rockies are both off Thursday. ... Hicks had to stop at second on his double in the eighth when a fan reached over the railing to grab it.