Soto hit a 454-foot drive in the third inning off Jon Gray (8-11), Soto's 26th home run this season. Soto is htting .362 with a 1.178 OPS since the All-Star break.
Colorado had matched its longest winning streak this season. The Rockies went 7-2 on their first winning trip this year and are 25-52 on the road and 45-27 at Coors Field.
Espino (5-5) allowed three hits in 5 2/3 innings, walked three and tied his season-high with seven strikeouts.
Kyle Finnegan, Washigton's fifth reliever, got three outs to complete a five-hitter and earned his 10th save in 14 chances.
Gray gave up two runs, three hits and two walks in four innings.
Yadiel Hernández hit an RBI single in the first, and Luis García singled in a run in the sixth against Lucas Gilbreath.
Nationals reliever Tanner Rainey, brought back from the minors, struck out the side in the seventh. It was his first major league appearance since Aug. 12.
AVILA TO RETIRE
Nationals catcher Alex Avila said he will retire after the season. The 34-year-old, an All-Star in 2011, is a son of Detroit general manager Al Avila. A veteran of 13 seasons who is hitting .179 with seven RBI, Avila said he expects to continue in baseball next season in a non-playing role. He said he has not spoke about a job with his father, who once traded him,
Nationals: RHP Stephen Strasburg (neck) is continuing his rehabilitation process after season-ending thoracic outlet surgery on July 27. Strasburg is not expected to throw until November. He has pitched 26 2/3 innings across the last two seasons after signing a $245 million, seven-year contract following Washington's 2019 World Series title.
Washington: RHP Erick Fedde (7-9, 5.16 ERA) opens a three-game series at Miami on Mondau.