PITTSBURGH -AP- Jayson Werth's wide grin belied the fact that theWashington Nationals right fielder is an old hand at clubhouse celebrations, having played on eight division-winning teams during his 14-year big league career.Werth's latest crown came Saturday night when the Nationals clinched their third National League East title in five years, beating the Pittsburgh Pirates 6-1 behind 5 1/3 scoreless innings from rookie reliever Reynaldo Lopez."It's never gets old," Werth said. "Never." Stephen Drew's two-run single capped a three-run first inning for the Nationals, who return to the postseason after a one-year absence. Their win ensured a playoff berth, and they won the division about 20 minutes later when the second-place New York Mets lost to Philadelphia."It's such a hard thing to accomplish," Werth said. "You spent six months trying to do it. It's why you go to spring training early, so you can do everything possible to put yourself in positon to win the division."The Nationals won the division in Dusty Baker's first season as manager. He replaced Matt Williams, who fired following a 2015 season that began with high hopes of Washington reaching the World Series for the first time in franchise history.Baker had been out of the game for two years after being fired by theCincinnati Reds following the 2013 season, four days after they lost to the Pirates in the NL wild card."That's what I came here for," Baker said, standing in a corner of the clubhouse and watching his players celebrate. "I'm telling you -- let these young men have a great time tonight, back to work tomorrow. First step in a four-step process. This step is the hardest to get. I'm just so happy for these guys. I love them. I love this team."Lopez (4-3) came on to the start the bottom of the fourth inning with a 6-1 lead and allowed three hits while striking out five and walking one. He was removed a runner on first and one out in the ninth inning."He was really impressive," Werth said. "We still have some questions about our roster going into the postseason. He's a great talent and if he pitches like he did tonight he can really help us."Marc Rzepczynski and Blake Treinen got one out each to end the game, and a pocket of Nationals' fans behind the visiting dugout cheered.Joe Ross allowed one run and five hits over 2 2/3 innings in his second start since missing 2 1/2 months with right shoulder inflammation.Drew's single came after Bryce Harper's sacrifice fly. Harper also drove in a run with a grounder during a three-run fourth that included three errors and increased the Nationals' lead to 6-1. Jayson Werth hit into a run-scoring forceout and Anthony Rendon had a sacrifice fly.Wilson Ramos had three hits for the Nationals, and Drew and Werth added two each.Pittsburgh lost for the just the third time in 10 games but fell four games out of the second NL wild card with eight games remaining.Rookie Josh Bell homered in the third.Ivan Nova (12-8) lost his second straight start, giving up six runs -- three earned -- and eight hits in four innings. He had gone 5-0 in his first eight starts after being acquired from the New York Yankees on Aug. 1 in a trade."I thought he was getting into a nice spot going into the fourth inning and we more or less took him out of the game with our defense," Pirates manager Clint Hurdle said.