NEW YORK -- The score was tied and the New York Mets had two runners on with one out in the sixth inning Sunday afternoon when thunderstorms arrived at Citi Field.

In other words, the Mets were right where the Pittsburgh Pirates wanted them.

The Pirates shrugged off rain delays Sunday, when they rode a four-run seventh inning to an 8-1 win and a three-game sweep of the Mets.

"We've been fortunate that we're really good at dealing with rain delays," Pirates manager Clint Hurdle said. "We've had a lot of rain delays."

Twenty hours and 17 minutes worth, as a matter of fact. The delay Sunday was the 17th for the Pirates in 115 games. Thirteen of those delays have come in the 57 home games the Pirates have played at PNC Park.

"That's a lot, isn't it?" Hurdle said. "We come in, we sit down, we keep (players) posted on what's going on. They find a way to just unplug for a little bit and then they stick that plug back in the wall and go."

After a 42-minute delay, right-hander Arquimedes Caminero (4-1) wriggled out of a jam by striking out catcher Travis d'Arnaud and getting shortstop Ruben Tejada to hit into a fielder's choice.

The Pirates then took advantage of the Mets' sloppy defense in the top of the seventh, which lasted more than half as long (24 minutes) as the rain delay. New York right-hander Bobby Parnell committed a throwing error and d'Arnaud was charged with a passed ball.

Right fielder Gregory Polanco delivered the go-ahead RBI single, pinch-hitter Mike Morse scored on the passed ball and Ramirez and first baseman Pedro Alvarez notched RBI singles.

"We've spent a lot of nights, especially at home, trying to grind out games," said second baseman Neil Walker, who coaxed a walk during the rally. "You kind of become numb to it to a degree."

The Pirates piled on in the eighth, when left fielder Starling Marte had an RBI single and Ramirez laced a two-run double.

Ramirez finished 4-for-5 -- the 25th four-hit game of his career and his first since Aug. 27, 2013. He is hitting .375 with 11 RBIs in his last 10 games and .257 with one homer and 13 RBIs in 18 games since the Pirates, with whom he played the first five-plus years of his career, acquired him from the Milwaukee Brewers on July 23.

"They're ready to play -- it doesn't matter the conditions," Ramirez said of the Pirates. "They put things behind them and just go out and play the game."

The Pirates (69-46) won Sunday despite resting three of their best every-day players -- former MVP center fielder Andrew McCutchen, shortstop Jung Ho Kang and catcher Francisco Cervelli.

The resourcefulness of the victory embodied a weekend in which backup catcher Chris Stewart keyed winning extra-inning rallies Friday and Saturday and Pittsburgh relievers combined to allow one run over 16 innings in the three games.

"Our guys picked everybody up -- they picked each other up throughout the day, throughout the weekend," Hurdle said.

Alvarez homered in the second inning and was one of four players -- along with Polanco, Marte and left fielder Travis Ishikawa -- to finish with two hits for the Pirates, whose lead over the Chicago Cubs in the National League wild card race increased to 1 1/2 games following the Cubs' loss to the Chicago White Sox.

Pittsburgh starter left-handed Jeff Locke gave up the one run on four hits and two walks while striking out five over 5 1/3 innings.

Despite being swept, the Mets (63-55) didn't lose any of their 4 1/2-game lead in the National League East thanks to the free-falling Washington Nationals, who were also swept by the San Francisco Giants.

"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," Mets manager Terry Collins said. "As bad as this game ended up looking, I'll take it."

D'Arnaud had two hits, including a second-inning homer.

Parnell (1-3) was charged with four runs, two earned, on two hits and two walks while striking out none over two-thirds of an inning.

Mets right-hander Matt Harvey allowed one run on seven hits and one walk while striking out six over six innings.

"It was a tough day for us," Harvey said. "We're still in a good position, so we've got to flush this one and move forward."

NOTES: Pirates RHP Arquimedes Caminero and Mets RHP Bobby Parnell also earned the decisions in the Pirates' 3-2, 10-inning win on Friday. ... Mets RHP Erik Goeddel (elbow strain) had his rehab moved to Double-A Binghamton from Class A St. Lucie, where he had a 7.71 ERA in five appearances. ... Pirates RHP A.J. Burnett (flexor strain) threw long toss Sunday morning and could throw off a mound this week. Manager Clint Hurdle remains confident that Burnett, who is retiring after the season, will make it back to the Pirates this year. ... A trio of injured Pirates -- IF/OF Josh Harrison, SS Jordy Mercer and RHP Rob Scahill -- continued their rehabs with Triple-A Indianapolis on Sunday. Harrison was 0-for-4, Mercer was 0-for-3 and Scahill allowed one run in one inning.