He legged out a double and scored Colorado's first run, broke a seventh-inning tie with a line-drive home run, and deftly guided right-hander Jhoulys Chacin through an erratic six-inning stint in which he allowed just two hits but walked six.

He topped off his night by throwing out a baserunner in the ninth that represented the tying run.

"He looks way better," Carlos Gonzalez said of Iannetta, who has thrown out five of the last eight runners. "He's concentrating more on what he needs to do at the plate. Defensively, he's always been really good, it's just being consistent behind the plate. Today was a good game for him. I hope he keeps playing that way because he can be important to our team."

Iannetta said his growth all stems from peace of mind.

"I think the biggest thing is not pressing," he said. "It's knowing I'm going to be back there offensively and defensively and allowing myself to go through a process to make adjustments as opposed to trying to force some adjustments in the video room or the cage or B.P. and then try to get the hit. ...

"That's the big thing is I know I'm going to be there every day and if I don't have a good at-bat, I'll have another one," Ianetta added. "Or if I don't have a good game, I'll have another one. Or if I don't have a good 15 at-bats, I'm still going to be playing."

Chacin threw 107 pitches, just 55 of them for strikes, but Iannetta helped limit the damage just as he did a day before with an unusually erratic Jorge De La Rosa in San Francisco.

Iannetta said he's always had faith in his defense and deft handling of the staff.

"It's always going to keep getting better and better the more I get a feel of the game, the more I develop a relationship with the staff, the more I learn of the opposing hitters," he said. "It's a maturing and growing process. I'm happy that I'm able to work through things."

The difference on this night was Iannetta's homer with one out in the seventh.

Iannetta, who stretched out a double that led to Colorado's first run two innings earlier, sent an 81 mph slider from lefty Chris Capuano (2-4) into the tunnel down the left-field line for his fifth home run.

The ball cleared the wall before he had taken his third step out of the batter's box.

"I was hoping to get a double out of it," Iannetta admitted. "I'll take a homer, though."

"I don't know that you can hit a line drive much harder than that, I really don't," Rockies manager Jim Tracy said. "I didn't think that was going to go out of the park because I thought he hit it so well that it had that top spin and it was going to hit the top of the wall. But he crushed it."

Capuano called it his only regret.

"It was a hanging breaking ball," he said. "I was trying to throw a backdoor breaking ball there and it stayed up in the middle of the plate right into his swing."

Matt Belisle (3-2) got two outs for the win, Colorado's fifth in five games against the Mets this season. They swept a four-game series at Citi Field in April.

Rafael Betancourt pitched a perfect eighth and Huston Street worked the ninth for his 12th save in 13 chances. Pinch-hitter Willie Harris led off with a check-swing single but was thrown out by Iannetta trying to steal second base with one out.

Daniel Murphy grounded out to a diving Troy Tulowitzki at shortstop on the ninth pitch of his at-bat for the final out. New York left the bases loaded twice and stranded 10, finishing 0 for 7 with runners in scoring position.

The Mets learned before the game that right-hander Chris Young might need season-ending surgery after re-injuring his pitching shoulder. Assistant general manager John Ricco said Young hasn't decided whether to try lengthy rehabilitation or have an operation to repair a tear in his anterior capsule.

The Rockies broke a scoreless tie in the fifth when Iannetta led off with a double, took third on Chacin's groundout following a punch-out by Ian Stewart, who is mired in a 3-for-44 season-long funk, and scored on Dexter Fowler's single to left.

New York tied it in the sixth. Carlos Beltran walked, went to third on Ike Davis' bloop single and scored on a high-hopper by Jason Bay to third baseman Stewart.

Capuano (2-4) allowed two runs and five hits in 6 2/3 innings.

The Mets threatened in the seventh but Helton threw out Murphy trying to score from third on Beltran's grounder to first. Iannetta was late with a slow tag, but got the call on a close play from plate umpire Mike Winters.

Game notes
Rockies RHP Aaron Cook (finger) will pitch three innings or throw 45 pitches in an extended spring training game in Arizona on Tuesday. ... Chacin's six walks tied his career high set in his first major league start, against Pittsburgh in 2009.