PITTSBURGH -- Even with expanded rosters in September, Pittsburgh third-string catcher Jacob Stallings knew he could get into Friday's game as it stretched into the 11th inning.

"I kind of did the math in my head. Bases loaded, two outs was the only way I was going to come up that inning," Stallings said.

Stallings hit a bases-loaded, two-out, full-count pinch-hit RBI single to left as the Pirates came from behind to defeat the Washington Nationals 6-5 at PNC Park.

It was his ninth major league at-bat, and it resulted in his second hit and second RBI.

Stallings, in anticipation of maybe getting to the plate, even "went down and hit on the tee before that inning," he said. "I knew I was the last guy, so I figured just in case. The first pitch, I got the nerves out of the way. I swung and missed."

He didn't miss once he got to a full count against Nationals reliever Yusmiero Petit (3-5).

The loss kept Washington from moving closer to clinching the National League East title.

Washington (89-64) still has a magic number of two for clinching, thanks to its loss and a win by the New York Mets.

Pittsburgh (77-76) won seven of its last nine games, but time is running out on its playoff hopes as it is 3 1/2 games out of a wild-card spot with nine games remaining.

Washington's Wilson Ramos broke a 3-3 tie with his 22nd homer, to right-center, to lead off the sixth. Reliever Jared Hughes walked in a run later that inning to make it 5-3.

Pittsburgh got back to within a run 5-4 in the bottom of the sixth when reliever Marc Rzepczynski walked pinch-hitter Jason Rogers with the bases loaded.

Former Pirates closer Mark Melancon made his first appearance back at PNC Park by pitching the ninth for the Nationals, but it wasn't a sweet return. He gave up the tying run on Sean Rodriguez's two-out RBI double to center, sending the game to extra innings.

"I kind of made a good pitch on the double, but you've got to tip your hat to Sean -- he got good wood on the ball and he's a line-drive hitter," Melancon said. "You just have to come back and get 'em tomorrow."

Rodriguez's double sailed over the head of rookie center fielder Trea Turner.

"Hindsight is 20-20. Sure, he could have been playing deeper, but he's inexperienced out there," Washington manager Dusty Baker said of Turner. "That's our fault for him not playing deeper. You learn from it. You turn the right way on a left-hander hitting the ball to center field. He's a novice out there. Sometimes you're going to make mistakes.

"I thought he had a bead on the ball. I was surprised the ball took off on him."

Wade LeBlanc (4-0) pitched the 11th for his first win with Pittsburgh.

Nationals starter Gio Gonzalez gave up three runs on five hits over five innings and left with a lead.

Pittsburgh rookie starter Jameson Taillon, who had pitched at least six innings in seven of his first nine starts at home, lasted five innings. He allowed three runs on six hits with seven strikeouts and no walks.

Pittsburgh lost a player to injury before it got a chance to bat. Left fielder Gregory Polanco left in the top of the first inning after crashing into the outfield wall. With two outs, Washington's Bryce Harper hit a double to left that was nearly a homer. Polanco leaped to try to catch the ball, crashing left-side-first into the wall. The club said he had a contusion on the left side of his face.

Washington put up three runs in the second.

Stephen Drew and Ryan Zimmerman hit back-to-back doubles for a 1-0 lead. Zimmerman's liner to right-center was his 1,500th career hit. Danny Espinosa followed with his 23rd homer, to dead center, making it 3-0.

"In the second inning trouble, the fastballs and curveballs were elevated," Pittsburgh manager Clint Hurdle said of Taillon. "Everything was just up in the zone. He said he felt strong. We'll go with that. "

The Pirates drew within 3-2 in the bottom of the second. Alen Hanson reached on an infield chopper, advanced on David Freese's bloop single and Josh Bell's fly out to right, then scored on Taillon's single up the middle.

Adam Frazier's single up the middle pushed Freese home to make it 3-2.

Pittsburgh tied it 3-3 in the third when Andrew McCutchen led off with a triple to center and scored on Jung Ho Kang's groundout.

NOTES: Washington 2B Daniel Murphy was out of the lineup for the fifth straight game. The Nationals have not divulged the nature of his injury. ... Pittsburgh LF Starling Marte was not in the starting lineup after he was removed from Thursday's game because of recurring back tightness, ... The Pirates recalled LHP Phil Coke from Triple-A Indianapolis a day after he was acquired from the Yankees in a minor league deal for cash considerations. To make room on the 40-man roster, Pittsburgh placed RHP A.J. Schugel (right shoulder) on the 60-day disabled list. ... Pittsburgh lists rookie Tyler Glasnow as its Sunday starter. The slot was previously TBA, then was listed as Steven Brault. Washington has not named a starter for that game. ... 1B/OF Josh Bell was named Pittsburgh's minor league player of the year, and RHP Mitch Keller was named the organization's minor league pitcher of the year. ...Thursday was the Nationals' final day off of the regular season.