NEW YORK — The Mets fell flat in a flash.
Soon after a sudden storm, some sloppy play by the NL East leaders helped propel Pittsburgh to an 8-1 victory Sunday that sealed the Pirates' first season series sweep of New York.
Pedro Alvarez, Aramis Ramirez and Gregory Polanco each had run-scoring hits in a breakaway four-run seventh, keyed by reliever Bobby Parnell's throwing error.
Pittsburgh also scored on a passed ball by Travis d'Arnaud in their sixth straight win over this potential postseason foe. The Pirates swept the Mets at home in a three-game set in May.
"We had a bad day. Came out of the rain delay, we didn't play good," manager Terry Collins said. "We had a terrible two innings in a row in a good weekend."
The Mets were in position, as they were all three games of this series, to beat the team with the second-best record in the National League — New York lost in extra innings the previous two nights.
Alvarez homered off Matt Harvey in the second, and d'Arnaud connected off Jeff Locke in the bottom half for a 1-all tie. Harvey and Locke then matched each other in a gritty duel until a surprising sun shower turned to a downpour in the bottom of the sixth, when the Mets had runners on first and second with one out.
"Today was definitely a struggle and, overall, it was a tough day for us," Harvey said. "We've got all the games to play and we're still in good position, so we gotta flush this one and move forward."
Booming thunder and crackling lightning got a scream from the crowd of 40,250 — and a jump and a dash from Daniel Murphy, on second base. The Mets second baseman was startled by the clap and flash and ran from the field before umpires even called for the tarp.
After the 42-minute delay, Arquimedes Caminero (4-1) got two crisp outs to end the Mets best chance.
The Mets then lost their footing.
Parnell (1-3), who got the defeat in the opener of the series Friday, was booed as he yielded four runs — two earned — in relief of Harvey.
Parnell's throwing error to second base in the seventh helped Pittsburgh score four times.
In two outings this series, Parnell, whose coming off Tommy John surgery, gave up five hits and six runs — four earned — while only getting two outs. He was booed off the mound after both appearances.
"If we turn the double play, we don't hear that," Collins said. "And I am a little concerned about Bobby."
Despite the three losses in a row, the Mets are 4 1/2 games up in the division over Washington, losers of six straight.
"I believe it in my heart, as I'm sitting here, if any of you guys in this room would've told me on May 15th that with 44 games left in the season, we'd have a 4 1/2 game lead, I'd take it," Collins said. "As bad as this game ended up looking, I'll take it."
Harvey gave up seven hits and a run in six innings but threw 103 pitches. He walked one, ended a three-start streak without offering a free pass.
"The getting the pitch count up, getting some hits early on was big," Pittsburgh's Neil Walker said. "It's a testament to the approach as a whole."
Pirates: RHP Vance Worley threw 75 pitches for Triple-A Indianapolis on Saturday night, his first action since being designated for assignment July 30 and accepting a demotion to the minors after clearing waivers.
Mets: 1B Lucas Duda (lumbar strain) did not start for a sixth straight game. He walked as a pinch hitter in the 12th Saturday and should be back in the lineup Tuesday, after an off day.
Pirates: Gerrit Cole tries for a majors-leading 15th win when Pittsburgh opens a seven-game homestand against Arizona. The right-hander has lost his last two outings but is 2-0 with a 1.98 ERA against Arizona in two career starts.
Mets: Jacob deGrom is on a 15-start roll, with a big league-best 1.46 ERA in that span. He makes his sixth career start against an AL team (2-2, 3.06), when New York faces the Orioles in Baltimore on Tuesday.
The Mets dropped to 9-20 vs. the NL Central. They are 48-29 against the rest of the league.
THAT HAD TO HURT
Gold Glover Juan Lagares crashed hard into the center field wall trying to catch Polanco's flyball in the fifth. The ball hit off Lagares' glove and then off the wall for a triple. Lagares remained in the game.