Neil Walker homered while Starling Marte and Russell Martin each had two hits for the Pirates, who have won four in a row. Pittsburgh's bullpen worked three perfect frames, with Jared Hughes (3-1) picking up the win and Mark Melancon earning his ninth save.

Washington ace Stephen Strasburg (3-4) lost despite his seventh straight quality start, allowing three runs on seven hits over seven innings with seven strikeouts. Greg Dobbs had two hits and Ian Desmond homered for the Nationals, who have lost four straight.

Strasburg outdueled fellow former No. 1 pick Gerrit Cole for most of the evening, but the Pirates finally got to him in the seventh. Martin led off the inning with a single and Marte doubled off the wall in right with one out, setting up pinch hitter Jose Tabata's sacrifice fly to tie it and Harrison's single up the middle to plate the go-ahead run.

Desmond broke a scoreless tie in the fourth, when he belted an 0-1 changeup from Cole out to left for his ninth home run, but Walker answered in the bottom of the frame by blasting his 10th on a 1-1 fastball for Pittsburgh's first hit. The Nationals put together a two-out rally in the fifth as Anthony Rendon singled, stole second and scored on Wilson Ramos' single for a 2-1 lead.

GAME NOTEBOOK: Cole threw a career-high 112 pitches over six innings and struck out seven while allowing two runs and five hits. … Pirates 1B Ike Davis went 1-for-3 with a walk and has reached base in 19 of his last 20 games. … The Nationals fell to 4-24 when scoring three or fewer runs, which they've done in four straight contests.