DENVER -- The Colorado Rockies played long ball late in rallying to tie it twice. The New York Mets managed to prevail because of a hard grounder by Ike Davis that happened to find the hole between third and shortstop.

Davis singled in the go-ahead run off reliever Matt Belisle in the 11th inning and the Mets overcame two tying homers allowed by their bullpen to beat the Rockies 6-5 on Sunday.

"It was tough to see. The shadows were pretty bad at that point and the first fastball, he just blew it by me," Davis said. "I was like, 'Oh boy, got to shorten up a little bit.' I put it on the ground and I knew it had a good chance if it didn't hit anybody. It happened to find a hole."

Mets ace Johan Santana, looking for his first win since September 2010, left with a 4-0 lead after six innings but left-hander Tim Byrdak gave up pinch-hitter Todd Helton's grand slam in the eighth. Kirk Nieuwenhuis put the Mets ahead again with an RBI double in the 10th before Frank Francisco served up Carlos Gonzalez's solo homer in the bottom half.

David Wright started the 11th with a single off Belisle (1-2) and went to third on Lucas Duda's single. After Scott Hairston hit into a fielder's choice, Davis' sharp grounder finally rescued the Mets.

"There were some very positive things on a day when we should have won this game a lot easier than we did," said a relieved Terry Collins, the Mets' manager.

Ramon Ramirez got his first save of the season, holding onto a lead after Byrdak and Francisco (1-1) couldn't.

Pinch-hitter Mike Baxter singled off Belisle in the 10th and scored when Nieuwenhuis followed with an opposite-field double to left.

"It was a wild game and a wild series," Baxter said after the Mets took two of three. "Every game here was pretty crazy. But it's a great win. It's obviously early in the season, but this is something we can look back on and definitely grow from as a group."

Dexter Fowler hit a one-out single off Jon Rauch to get the Rockies' eighth-inning rally started. Gonzalez drew a walk and Troy Tulowitzki grounded out before Michael Cuddyer walked to load the bases.

Byrdak came in to face Helton, who worked the count to 2-2 before driving an 84 mph slider off the facing of the second deck above the right-field wall, bringing the crowd to its feet with a roar.

"I was looking for it and got it," Helton said. "I was concerned about chasing up and I was hoping he'd throw me that pitch in that situation."

A pumped-up Helton flipped his bat as he began his trot and slapped hands with a gaggle of teammates around home plate before emerging from the dugout moments later to take a curtain call.

It was the second pinch-hit homer of Helton's career and his sixth grand slam.

"It was an up-and-down game," Helton said. "Santana looked like he was throwing the ball really well. To get back into that game was big, but they just kept battling. They didn't quit."

Helton's slam was the second by the Rockies in the series. Ramon Hernandez also hit one in Friday night's 18-9 win.

"But he tied the game. He didn't put them ahead," Collins said. "So we still had a chance. We still had life and we came back and we fought hard."

Santana, who missed last season after undergoing shoulder surgery, gave up two hits, walked three and struck out five.

"Overall, I felt good. I made my adjustments and competed," Santana said. "We won and that's all I care about."

Starting for the first time at Coors Field, Santana still has not given up an earned run to the Rockies in 22 innings over three career starts.

Rockies starter Jamie Moyer went five innings and gave up four runs on 11 hits, including Josh Thole's two-out solo homer in the fifth.

The Mets scored three runs in the first, the first time New York scored while Santana was in the game during any of his five starts this season.

The sequence was punctuated by Wright's two-run double and an RBI single by Hairston, though Moyer managed to wriggle out of a one-out bases loaded jam by fanning Thole and retiring Santana on a fly ball.

"I think we do a pretty good job of bouncing back," Helton said. "It was a tough loss, but we'll be fine tomorrow."

Notes

• New Broncos QB Peyton Manning visited both the Mets and Rockies clubhouses before the game. Manning is a friend of Mets pitcher R.A. Dickey and is close with Helton, who was the backup quarterback to Manning when they were both in college at Tennessee.
• CF Andres Torres (strained left calf) completed his minor league rehab assignment and was set to join the Mets in Houston, where it's expected he'll be activated from the 15-day disabled list Monday. The team said it will option INF Zach Lutz to Triple-A Buffalo to make room for Torres.
• Rockies pitcher Drew Pomeranz, who left his start Friday after four innings because of tightness in his left forearm, is on course to make his next scheduled start Wednesday against the Los Angeles Dodgers.
• Juan Nicasio (1-0) is slated to pitch the series opener against Aaron Harang (1-1) and the Dodgers on Monday as the Rockies continue their nine-game homestand at Coors Field.
• Dickey (2-1) goes for the Mets in the series opener at Houston against Bud Norris (1-1).