DENVER -- Hector Sanchez was 22 years old when he was chosen to back up Buster Posey despite never playing a full season at any top minor league level.

The assignment was a boost to the Giants and put a ring on Sanchez's finger, but as he occasionally struggled defensively and hacked through at-bats the past two seasons, Sanchez looked the part of a talented youngster who could benefit from playing every day away from major league lights.

It's days like Wednesday that remind everyone why the Giants don't feel that's necessary.

Sanchez hit a grand slam in the 11th inning at Coors Field, providing the sixth and final Giants' home run in a much-needed 12-10 win over the Colorado Rockies.

The 24-year-old was 1 for his past 21 entering the game, the lone hit a walk-off RBI single in the 12th inning April 15.

"He seems to keep being the guy up in huge moments," Hunter Pence said. "And he's good -- he's really good in the big moments. I couldn't be happier for the kid."

Pence reached base five times and was one of many Giants who broke out as the lineup matched its run total from the previous seven games combined and avoided a series sweep.

Michael Morse set the tone with two homers in the first three innings, and along with Sanchez, he gave the Giants a pair of multi-homer hitters in a game for the first time since Pedro Feliz and Moises Alou each hit two in a 2005 game. Brandon Belt hit a go-ahead two-run homer in the seventh and became the first Giant to hit seven homers in the team's first 22 games since Barry Bonds in 2007.

Even Matt Cain, who was charged with seven earned runs, drew a plateful of clubhouse praise for regrouping and getting through six innings after falling behind 5-1 in the first two.

"I couldn't be prouder of these guys," said manager Bruce Bochy, who was ejected for arguing a called third strike in the fourth inning. "They were down 5-1, looking at a sweep -- but I'm (proud) of how hard they fought. They really grinded hard."

Before the four-hour, 26-minute game, Bochy was asked if Sanchez could benefit from playing every day at Triple-A Fresno. He insisted the backup catcher would get plenty of time on the field, not just on Posey's days off but as a valued pinch-hitter. The time without his gear on is almost as valuable, Sanchez said.

"I have to be honest, it's tough sometimes, but this is my job," Sanchez said. "And I'm learning -- I learn every day up here. With Buster, I ask him questions all the time. He's my tutor."

Posey laughed when told he's the teacher, pointing out that he's only three years older than Sanchez. But the two have formed a bond, Posey said, and the former N.L. MVP is happy to help bring the developing switch-hitter along.

"His job is a tough job," Posey said. "Baseball is a game that you need to play a lot, but ever since he came up he's done a great job, especially as a pinch-hitter. He's gotten a lot of clutch hits."

Posey, mired in a 3 for 35 slump, got the day off, along with Angel Pagan (sore knee).

When Cain gave up seven hits in the first two innings, the team looked headed for a quiet flight home. But Morse brought some thunder back to the dugout, hitting homers that were estimated at 458 and 450 feet. According to ESPN Stats and Info, he's just the third player since 2006 to hit multiple 450-foot homers in one game. With Morse's three-run homer in the third, the Giants tied the game at 5 and reached their highest run total in 10 days

"Something was going to spark us, going to ignite us," said Morse, who already has matched last season's combined homer total (five) from nine Giants left fielders. "Today, I think, was that day."

The teams exchanged mini-rallies into the late innings, with the Giants immediately regurgitating the lead after Belt and Sanchez's homers in the seventh and eighth.

Pence hit a leadoff single in the 11th and Belt drew a walk to keep the defining rally going. After a sacrifice bunt, Joaquin Arias (inserted for a sick Pablo Sandoval) was intentionally walked. In the dugout, the Giants quietly smiled. They knew Sanchez's .161 average didn't tell the whole story, and the powerful catcher was a better matchup against Chad Bettis, who relies on his fastball.

Sanchez fouled off three of those fastballs with two strikes, and on the 10th pitch of the at-bat he smoked a 94 mph two-seamer over the center field wall.

"Everybody wants to be the hero," Sanchez said, smiling. "I just felt the ball fly. I hit it well."

FRIDAY'S GAME
Cleveland (Carlos Carrasco 0-2) at Giants (Tim Hudson 2-1),
7:15 p.m. CSNBA