NEW YORK — Pitching on a rainy night in a nearly empty ballpark, Mike Pelfrey stayed focused on his preseason goals: 15 wins, 200 innings.

The big right-hander checked off that 15th victory Thursday, tossing seven strong innings and hitting a tiebreaking single to help the New York Mets finish a four-game sweep with a 6-2 win over the Pittsburgh Pirates.

Slumping rookie Lucas Duda had a two-run double and the Mets rallied for their first four-game sweep since June 2006 at Arizona. New York (74-73) has won seven of nine to move over .500 for the first time since Aug. 24.

Angel Pagan added three hits, two RBI and a dazzling catch in center field. Pelfrey (15-9) extended his career high for wins by following up a victory over Philadelphia with a solid effort against the punchless Pirates.

"We're playing the best baseball we have in a while — even if the Pirates have made some mistakes," Mets manager Jerry Manuel said.

Pittsburgh, with the worst record in the majors at 48-98, fell to 15-59 away from home. The Pirates must win three of their last seven road games (three in St. Louis, four at Florida) during the final week of the season to avoid matching the 1963 Mets for the worst road record (17-64) in a 162-game season.

Pelfrey allowed two runs and six hits. He also put New York up 3-2 with a two-out single off Sean Gallagher through the left side in the sixth. That scored Duda, who doubled with one out off Wilfredo Ledezma (0-3).

Ike Davis added a sacrifice fly in the seventh after a balk by Chris Resop. Pagan hit a two-run double in the eighth to make it 6-2.

Pedro Feliciano struck out two in a perfect inning and Bobby Parnell finished with a 1-2-3 ninth. The four-game winning streak is New York's longest since an eight-game run June 10-18.

The Pirates dropped to 0-7 at Citi Field, which opened last year.

"We were right there, but Pelfrey's good. He made the pitches he had to make," manager John Russell said.

With a "crowd" that numbered in the hundreds at the start, cavernous Citi Field was eerily quiet at times — except for the vendors hawking Crackerjack and a cheering section in left field for Pirates third baseman Pedro Alvarez, who went to high school in New York.

Some of those who did want to come out might not have been able to. A powerful storm tore through the city less than two hours before game time, knocking down trees and power lines. Service was shut down on the elevated No. 7 subway train and the Long Island Rail Road, both of which carry passengers to Citi Field.

Fans were warned before the game to take cover on the concourses, but play began only 12 minutes late.

Alvarez doubled in the second and scored on John Bowker's single. Ronny Cedeno hit an RBI triple in the fourth, but the Pirates could have had a big inning if not for a spectacular play by Pagan on Bowker's drive to deep right-center with two on.

"Things just didn't go our way. All we can do is keep on playing and hope the wins come," Pirates first baseman Garrett Jones said.