WASHINGTON (AP) — Trea Turner's go-ahead grand slam in the sixth inning lifted Washington to a 6-5 victory over the Philadelphia Phillies for a doubleheader sweep Tuesday that helped the Nationals clinch an NL wild card, capping quite a turnaround for a team that was 19-31 in late May.

"We knew nothing was going to be won or lost in the first five months," said Turner, who had three hits in the day's first game, a 4-1 win for the Nationals, "and now we're in a good spot."

Washington assured itself of returning to the playoffs for the fifth time in eight years after sitting out October in 2018.

The Nationals entered Tuesday hoping to beat Philadelphia twice plus get a loss by the Chicago Cubs at Pittsburgh — and each of those things happened.

Right after center fielder Victor Robles made a running catch for the last out of the second game, the Nationals Park scoreboard showed the game in Pittsburgh, and Washington's players watched the end of the Cubs' 9-2 defeat, then started celebrating on their field.

Anthony Rendon delivered two sacrifice flies to raise his majors-leading RBIs total to 124 in the opening victory, a result that also eliminated Philadelphia and $330 million outfielder Bryce Harper, the ex-Nationals star, from postseason contention.

In the nightcap, Washington trailed 4-2 entering the sixth, because Brad Miller managed to hit two homers off Max Scherzer (11-7) — and at that moment, about 250 miles away, the Cubs were leading the Pirates 1-0.

Everything changed within minutes.

While Washington was loading the bases against Aaron Nola (12-7) with two walks and a single — setting the stage for Turner's 18th homer of the season and second career slam, which came off Jared Hughes — the Cubs were imploding during the Pirates' seven-run seventh.

Turner's drive to left made it 6-4, and he celebrated with the Nationals' customary dugout dance line and a curtain call.

But the rest of the evening wouldn't be entirely smooth sailing for Washington, which was fitting given the roller-coaster nature of its entire season so far.

Harper, who appeared in the visiting clubhouse after the first game just as reporters were told it was time to leave, drew loud boos from spectators all day, especially when he stepped in as a pinch hitter in the second game. That was with two outs in the seventh to face, of all people, Hunter Strickland, with whom the 2015 NL MVP has a complicated history that includes playoff homers and a brawl when the slugger was with Washington and the reliever was with San Francisco.

Harper got the best of this matchup, turning on a 98 mph offering and depositing it in the second deck in right-center an estimated 442 feet away.

That made it 6-5, and Washington's beleaguered bullpen made it stand up. The Nationals got three outs from Javy Guerra in the eighth, and the last three from Daniel Hudson, who closed out both ends of the doubleheader to raise his save total with Washington to five in seven chances.

Washington was 12 games below .500 after a loss on May 23 concluded a four-game sweep at the New York Mets.

At that point, the Nationals were fourth in the NL East, ahead of only the woebegone Miami Marlins, and the calls for manager Dave Martinez to lose his job were loud.

There were all sorts of problems in the early going, from defensive sloppiness to bad baserunning to, above all, unreliable-as-can-be work from the bullpen in middle and setup relief.

But Martinez retained his always-sunny disposition and remained in his post, unwilling to publicly criticize his players and, in a participation-trophy sort of way, often pointing out how hard they had tried in defeat that day or noting, as if it truly mattered, that they had trimmed a deficit in what wound up as a loss.

Eventually, things clicked. Washington went on a real roll, even playing winning baseball while Scherzer took two trips to the injured list with a back muscle problem.

"We've been having dress rehearsals for the playoffs since, like, May," Washington reliever Sean Doolittle said. "I'm being serious. We had our backs so far up against the wall so early in the season, I really feel like we've kind of played out every possible scenario that might come up."

GAME 1 RECAP

Tanner Rainey (2-3) struck out two in a 1-2-3 sixth for the win in the makeup of a June 18 rainout. Nick Vincent (1-4) took the loss in the first game.

HE SAID IT

Asked about his future as Philadelphia's skipper, Gabe Kapler replied: "There's going to be plenty of opportunity to reflect. I love this organization. I love this team, specifically. I love working for this front office. I love working for this ownership group. I'm going to manage this club as long as I can, because I think I give us a great chance to win and I care deeply about the success of this franchise."

TRAINER'S ROOM

Phillies: RHP Juan Nicasio (rotator cuff tendinitis) was activated from the 10-day IL.

Nationals: C Kurt Suzuki (right elbow) got the day off.

UP NEXT

Washington RHP Aníbal Sánchez (10-8, 3.91 ERA) faces LHP Drew Smyly (4-7, 6.44) on Wednesday.