Mike Pelfrey earned his 15th win, pitching seven strong innings and hitting a tiebreaking single to help the New York Mets finish a four-game sweep with a 6-2 victory over the Pittsburgh Pirates on a rainy Thursday night at nearly empty Citi Field.

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 — likely too late to get back in the playoff race — to move over .500 for the first time since Aug. 24.

Angel Pagan added three hits, two RBIs and an outstanding 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.

Pittsburgh, with the worst record in baseball 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, and 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.

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 the Mets' second-year ballpark.

Fans were warned before the game to take cover on the concourses, but play began only 12 minutes late. Those in attendance were soon invited down to fill expensive seats in the lower level — many moved back up the aisles later to get under the overhangs during a steady drizzle.

Alvarez doubled in the second to the delight of his rooters 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.

After a long dash, Pagan made a sliding catch on the warning track in front of the 415-foot sign. Then he started an 8-4-3 relay that doubled off Alvarez at first base, with Pagan pumping his fist from the seat of his pants as the Mets completed the play.

Davis and Josh Thole singled in the bottom half off starter Charlie Morton, who entered with a 9.05 ERA in 13 major league starts this season. Duda hit a grounder past diving first baseman Garrett Jones and into the right-field corner for his second hit in 35 big league at-bats.

NOTES: Struggling pitcher Zach Duke (7-14, 5.78 ERA) will make his next scheduled start for Pittsburgh on Sunday against Arizona. The Pirates considered pulling Duke out of the rotation, but pitching coach Ray Searage said he and Duke made some mechanical adjustments that could help the left-hander. "He's not hurt. We're just going to see how this thing plays out, start by start," Searage said. "He's still fighting. He's still battling." ... The last time Pittsburgh was swept in a four-game series by the Mets was in June 1997 at Shea Stadium. ... Pirates RHP Brian Bass cleared waivers and accepted an outright assignment to Triple-A Indianapolis. ... New York's previous four-game sweep at home was in August 2003 against Colorado at Shea Stadium. ... Mets CF Carlos Beltran rested. Jesus Feliciano played right, with Pagan in center. ... Before the game, manager Jerry Manuel said Duda probably will platoon with Nick Evans in left the rest of the way. ... Because of the poor weather, the Mets announced that tickets from Thursday night's game can be redeemed for free tickets to a game Sept. 27-30 against Milwaukee.