PHILADELPHIA — When Aaron Nola can't stop Philadelphia's skid, the Phillies are in trouble.
Stephen Strasburg threw seven impressive innings, Bryce Harper, Ryan Zimmerman and Juan Soto homered and the Washington Nationals beat the freefalling Phillies 5-1 on Wednesday night to complete a three-game sweep.
"We haven't played good baseball due to a ton of variables," Phillies manager Gabe Kapler said.
Nola, a Cy Young Award contender worthy of MVP consideration, had a rough first inning as the Phillies lost their fifth in a row to drop 7 1/2 games behind first-place Atlanta in the NL East with 17 to play. They're 11-23 since Aug. 5, when they had the NL's second-best record.
"I made mistakes and they didn't miss them," Nola said. "We still have a chance. We have some games left."
The Phillies trailed the Mets by seven games with 17 to play in 2007 and rallied to win the NL East to begin a stretch of five straight division titles. They were swept by Colorado in the division series that season but won the World Series in 2008 and the NL pennant in 2009.
"It can change real fast," Nola said. "We can go from three (games back) to seven and seven to three just as fast."
Philadelphia has seven games remaining against the Braves.
Nola allowed four runs and six hits in five innings. His ERA rose to 2.42. He's given up four runs twice in September after only doing it twice in his first 27 starts.
"Their lineup is exceptional," Kapler said. "They throw challenging at-bats at you and they can all take you deep."
Nola, Mets ace Jacob deGrom and Washington's Max Scherzer are the front-runners in the NL Cy Young race. Scherzer has won the past two and previously won the award in the American League with Detroit in 2013.
Strasburg (8-7) allowed one run and struck out nine in his best start since April. He improved to 12-2 against the Phillies.
Harper crushed his 33rd homer, a two-run shot into Philadelphia's bullpen in the first to give the Nationals a 2-0 lead. Anthony Rendon followed with a double and scored on Zimmerman's single.
Zimmerman connected in the fourth, sending a drive into the bushes in straightaway center. Odubel Herrera made a leaping attempt at the fence and nearly caught it.
Soto drove one into the second deck in right field in the sixth off Austin Davis to make it 5-1. The 19-year-old rookie has 19 homers. Harper hit 22 homers as a teenager for the Nationals in 2012.
"It's reminiscent of watching Tony Gwynn growing up," Strasburg said of Soto.
J.P. Crawford hit a solo shot in the fifth for Philadelphia's only run.
TOUCH 'EM ALL
Strasburg threw a pitch that hit Philadelphia's Jorge Alfaro, bounced off his arm, hit catcher Matt Wieters on the side of his helmet and then glanced off the plate umpire's mask.
Nola became the first Phillies pitcher to reach 200 strikeouts in a season since Cliff Lee and Cole Hamels in 2013.
The Nationals closed within a half-game of the Phillies for second place behind the Braves.
Nationals: RHP Joe Ross makes his first start of the season Thursday in a makeup game against the Cubs.
Phillies: RHP Zach Eflin (9-7, 4.42 ERA) pitches Friday night against Miami in the opener of a three-game series. Eflin is 1-0 with a 2.57 ERA in two starts vs. the Marlins this season.