DENVER -- As the Rockies were busy stranding runners Sunday, Omar Quintanilla was back in the team's batting cage, preparing for his chance.

"I probably took a million hacks in there," Quintanilla said.

Quintanilla has been hidden in the background most of this season, but he shined on center stage Sunday. Quintanilla hit a towering solo home run in the bottom of the 12th inning to propel the Rockies to a 4-3 win over the Reds at Coors Field.

He was the unlikeliest of heroes. The Rockies left a franchise-record 18 men on base, and Quintanilla, who was stuck in an 0-for-16 slump and had just one big league home run in 427 at-bats, certainly didn't look like the man to play the role of Superman.

But Reds reliever Mike Lincoln (1-5) left the ball up and in on a 1-0 pitch, and Quintanilla, who entered the game in the top of the 12th as a defensive substitution, put every ounce of his 5-foot-10 frame into the swing.

"It's an unbelievable feeling," said Quintanilla. "There's nothing else that can beat that."

After trotting the bases, Quintanilla was greeted by a mob of ecstatic teammates. They knew such a special moment couldn't have happened to a better guy -- a guy who works hard, shows up every day and never complains about his role.

"It's so appropriate," Rockies manager Clint Hurdle said. "For him to come in and barrel that thing like he did and pick everybody else up makes you feel good and gives you a sense of value being on the team."

Trailing, 3-2, in the ninth, Colorado tied it, thanks to a comedy of mental miscues by the Reds. Matt Holliday reached first on a fielding error and advanced to second on a balk. He then raced to third when Brad Hawpe flied out to right and trotted home when Jay Bruce's throw sailed into the stands.

Colorado loaded the bases later in the inning, but couldn't score the winning run. The Rockies also loaded the bases in the first inning, but only mustered one run when Bruce botched Garrett Atkins' shallow fly to right, allowing Scott Podsednik to score from third.

Cincinnati served the game on a platter, committing five errors, walking nine and throwing two wild pitches, but the Rockies were largely unable to take advantage, going 0-for-16 with runners in scoring position.

"Today, it just wasn't happening for us," Ian Stewart said. "But we got the big hit when we needed it."

Rockies starter Ubaldo Jimenez was sharp early, but left the game trailing, 3-1, after giving up three walks and a solo home run to Chris Dickerson in the sixth. He gave up three runs (two earned) on four hits and struck out six in the outing.

"He did a good job," Hurdle said. "It was another outing without his best stuff that he battled and kept us in the ballgame."

Colorado's bullpen pitched outstanding to pick up Jimenez. Six relievers combined to strike out eight and only give up one hit in six innings.

"Everyone's feeling good out there right now," said Taylor Buchholz, who pitched two scoreless innings. "We were just going out there and doing our job, and everyone stepped up when they needed to."

The Rockies have won three straight series and are eight games back of Arizona, who lost Sunday, in the National League West. Colorado begins a six-game road trip in San Francisco on Monday and will look to build off the momentum of the brief homestand.

"We needed this win," Stewart said. "We're still fighting."