Updated

WASHINGTON (AP) -- Stephen Strasburg tossed a complete game six-hitter and also homered, Wilmer Difo added a home run and the Washington Nationals defeated the Miami Marlins 4-0 on Wednesday to complete a three-game sweep.

Washington, which has won four in a row, extended its lead in the NL East to 15 games over the Marlins. Miami, which had won 13 of 16 prior to arriving in Washington, had not dropped three in a row since July 14-16.

The Marlins had no answer for Strasburg (11-4), who struck out eight. Strasburg threw 110 pitches. It was Strasburg's second complete game in 179 starts and his first since Aug. 11, 2013, against Philadelphia.

Strasburg is 1-1 with a 0.86 ERA in three starts since returning from a disabled list stint for right elbow nerve impingement.

Miami's Giancarlo Stanton, who leads the majors with 51 home runs and has 18 this month, went 0 for 4.

Miami left-hander Adam Conley (6-6) made it through the first four innings unscathed before Strasburg launched the first pitch of the fifth to right-center for his second home run this season and third of his career. Two batters later, Difo connected for his fifth homer of the year.

Anthony Rendon had a two-out RBI double in the seventh and Alejandro De Aza scored on a passed ball in the eighth to pad Washington's lead.

J.T. Realmuto had three hits for the Marlins, who went 2-8 at Nationals Park this season.

DIFO DELIVERS

Difo was 2 for 4, extending his hitting streak to eight games. In that span, he is hitting .394 (13 for 33). The Nationals improved to 25-6 when Difo starts and bats in the No. 2 spot.

TRAINER'S ROOM

Marlins: Manager Don Mattingly said the team has not finalized plans for 1B Justin Bour (right oblique strain) to begin a rehabilitation assignment, but hopes it will happen before the minor league season ends. "We're running out of time, so it's going to be fairly soon here," Mattingly said. "Hopefully after this series or a couple days after he'll go out because he needs to try to get his timing back."

Nationals: OF Bryce Harper, on the disabled list since Aug. 13 with a hyperextended left knee, said he had no set target date for a return. "The knee's feeling OK," Harper said. "Going through a calf strain and, of course, the bone bruise, it takes time. It's all it's been. I'm just trying to take some time. It's only been two weeks plus three days. It's still fairly new. I'm just trying to take it day by day."

UP NEXT

Marlins: RHP Odrisamer Despaigne (0-1, 3.70 ERA) starts against Philadelphia on Thursday as Miami returns home to begin a seven-game homestand.

Nationals: Washington opens a four-game series at Milwaukee on Thursday as LHP Gio Gonzalez (13-5, 2.40), who allowed two runs in seven innings against the Brewers on July 26, gets the nod.