MIAMI -- Right fielder Bryce Harper showered, changed and slipped out of the Washington Nationals' clubhouse before the media could ask him a single question.

That may be disappointing to some. Then again, Harper isn't exactly thrilled with how things are going, either, especially after his Nationals lost 2-1 to the Miami Marlins on Friday night at Marlins Park.

It was the Nationals' fourth straight loss, and they fell 8 1/2 games behind the New York Mets in the all-but-decided race for the National League East title.

Harper didn't help much Friday, striking out three times and stranding four runners against a Marlins team that is way out of contention.

"Bryce has had a fantastic year for us," said Washington manager Matt Williams, whose team fell to 71-69. "We'll try to give him those opportunities every day, that's for sure."

The Marlins (60-81) scored the winning run in the seventh inning. Catcher J.T. Realmuto led off by pulling a double to left off of reliever Casey Janssen (1-5). Realmuto reached third on a sacrifice by right fielder Ichiro Suzuki, who popped up the bunt. Janssen fielded the bunt, but his throw to third was late.

Marlins shortstop Miguel Rojas followed with the game-winning sacrifice fly. Harper made a sliding catch in shallow right, but by the time he got up, it was too late to get Realmuto.

"Initially, I wasn't running until I saw Harper slide," Realmuto said. "It's a tough play to slide and make that throw home. (Harper's) an incredible athlete, but I'll take my chances."

Harper, perhaps the leading candidate for NL Most Valuable Player, drew a walk in the first inning. But then he struck out on a 94-mph fastball by starter Jarred Cosart in the third.

"That (pitch) was right on the corner," Williams said. "We went in and looked at it (on video). It was a pitcher's pitch."

Cosart got him again in the fifth, stranding two runners when he tied up Harper on an 81-mph breaking pitch.

In the seventh, with runners again on first and second, Harper struck out on reliever Mike Dunn's 95-mph fastball. Dunn (2-5) set a Marlins career record with his 20th relief win.

Dunn has a good history against Harper, holding him to a .115 batting average in their careers -- two hits in 17 at-bats; Harper has just one RBI in this lefty-on-lefty matchup -- a solo homer.

"I went with what has worked in the past and went right at him," Dunn said. "He's a good hitter. But I felt if I made good pitches, I could get us out (of the jam)."

Neither starting pitcher got a decision. Cosart, in his second start since coming off the disabled list after suffering an inner-ear disorder, came out after five scoreless innings.

Nationals left-hander Gio Gonzalez, who is from Miami Dade County (Hialeah High), allowed just one run in 5 1/3 innings.

Miami opened the scoring in the fourth. Third baseman Martin Prado drew a one-out walk, raced to third on a single by first baseman Justin Bour and scored when center fielder Marcell Ozuna beat out what was nearly an inning-ending double-play grounder.

Washington tied the score 1-1 in the sixth by scoring an unearned run. Third baseman Yunel Escobar led off with a single, advanced to second on a fielding error by Bour and ultimately scored on a sacrifice fly by catcher Wilson Ramos.

After Miami took the lead in the seventh, Brian Ellington pitched a scoreless eighth, and A.J. Ramos did the same in the ninth to earn his 26th save of the season.

The Marlins have won eight of their past 10 games.

"I think this is a great challenge for us -- to go head to head against teams that are fighting for a playoff berth," Jennings said. "It shows the fight and fire that our guys have."

NOTES: Nationals 1B Ryan Zimmerman (right oblique) hasn't played since Monday and still can't swing a bat. ... Nationals 1B Clint Robinson's wife is having a baby, and he's with her in Arkansas. His status for this weekend is uncertain. ... Tyler Moore, Washington's third-string 1B, got the start. ... Nationals INF Danny Espinosa, who bruised his right hand on Wednesday, is day to day. ... Nationals RHP Tanner Roark will start on Saturday against Miami RHP Jose Fernandez, who is 15-0 with a 1.14 ERA in his career at Marlins Park. ... Marlins RF Giancarlo Stanton, out since June 26 (fractured left wrist), has increased the intensity of batting practice, hoping to make a return before the season expires. ... Marlins SS Adeiny Hechavarria, who has missed seven straight starts (hamstring), will try to run full speed in a day or two and hopes to play within one week.