NEW YORK -- Playing in postseason-caliber games in mid-August doesn't faze the Pittsburgh Pirates, who are used to treating every game as if it's in October.

Backup catcher Chris Stewart delivered the go-ahead RBI single in the top of the 14th inning Saturday night when the Pirates beat the New York Mets 5-3 in front of an energized crowd of 38,878 at Citi Field.

It was the second extra-inning win in as many nights for the Pirates, who beat the Mets 3-2 in 10 innings on Friday, and their seventh straight victory in extra innings.

"The crowd, it's a playoff crowd -- they were into it," Stewart said. "But as far as our mindset is, we play playoff-intensity baseball every single night. So we're going to take it out there and do whatever we have to do to try to win a game that night."

On Saturday, that required just about everybody on the roster. The 14th inning began with only Stewart and infielder Pedro Florimon left on the bench, and Florimon scored the winning run after he pinch-ran for catcher Francisco Cervelli following Cervelli's double.

The win went to right-hander Joe Blanton, who was out of baseball last season and was picked up by the Pirates in a cash deal with the Kansas City Royals on July 29. Blanton, making just the 30th relief appearance of his 11-year career, allowed one hit and struck out six -- the most strikeouts he has recorded out of the bullpen -- in three innings.

"Just an experienced guy out there with a slow heartbeat making pitches late in the game," Pirates manager Clint Hurdle said.

There were only two pitchers left after Blanton -- left-hander Antonio Bastardo and right-hander Mark Melancon, the latter of whom converted his 35th straight save and his 37th overall with a one-hit 14th.

"A strong effort from all our guys," Hurdle said. "A real strong team win."

After Cervelli doubled leading off the 14th against left-hander Sean Gilmartin (1-1), left fielder Starling Marte followed with a chopper to third base. Daniel Murphy -- who usually plays second or third base -- fired to third to try to get Cervelli. But the throw drew third baseman Juan Uribe off the bag.

"It was the wrong play -- put us in a bad spot," Murphy said. "I should have gotten it, put it in my pocket, keep it to one run right there."

Marte went to third on Stewart's single and scored when second baseman Sean Rodriguez blooped a single into shallow center.

With the win, the Pirates (68-46) remained 1 1/2 games ahead of the Chicago Cubs in the National League wild-card race and six games behind the St. Louis Cardinals in the NL Central. Pittsburgh is trying to reach the playoffs for the third straight season.

"We've been fortunate to play a lot of these games," Hurdle said. "Our eyes aren't big when we come to this venue."

Nor are the Pirates fazed by close games. They are 34-18 in games decided by two runs or fewer.

"A team that has talent and they really grind games out, that's a special thing to have," Blanton said.

Third baseman Aramis Ramirez hit a two-run homer in the first inning for the Pirates and right fielder Gregory Polanco (3-for-6) homered leading off the third.

Right-hander Charlie Morton allowed three runs, four hits and one walk while striking out nine in 6 1/3 innings.

The Mets, who are trying to reach the playoffs for the first time since 2006, also used every player on their bench in losing for just the sixth time in the last 20 games. Backup catcher Anthony Recker made the final out by flying out to center as a pinch hitter.

New York (63-54) swept a four-game series from the Colorado Rockies before the Pirates hit town. The Mets still lead the Washington Nationals in the NL East.

"We've played hard, we've played well," Mets manager Terry Collins said. "You come in here, you get the homestand off to a good start and then you lose two extra-inning games. They're tough."

The Mets trailed 3-0 until the seventh when Uribe hit a leadoff homer and left fielder Michael Conforto whipped the crowd into a frenzy with a two-run blast.

"It was amazing, hearing the crowd go crazy and just evening the score and giving us a chance there," Conforto said.

Left-hander Jonathon Niese allowed three runs, five hits and two walks while striking out five in six innings.

NOTES: Mets 1B Lucas Duda (lumbar strain) sat out his fifth straight game. With LHP Jeff Locke scheduled to start for the Pirates on Sunday, Duda is expected to sit out until Tuesday, when the Mets begin a two-game series against the Baltimore Orioles. ... Mets LHP Steven Matz (left lat tear) began a rehab assignment with Class A St. Lucie on Saturday, allowing one run in one inning and throwing 23 pitches. He last pitched for the Mets on July 5. ... Pirates LF Starling Marte (left hand) was out of the starting lineup for a third straight game. ... Injured Pirates SS Jordy Mercer (left knee) went 1-for-3 and INF/OF Josh Harrison (left thumb) went 0-for-4 Saturday for Triple-A Indianapolis.