Pirates 3, Nationals 1: Andrew McCutchen knocked in two runs and made a sliding catch in center field for the final out and Edinson Volquez pitched six strong innings as host Pittsburgh claimed the opener of a four-game series.

Volquez (2-4) struck out four and allowed one run on three hits to snap a five-start winless streak, and two relievers bridged the gap to Mark Melancon, who worked around a pair of walks in a scoreless ninth for his eighth save. Josh Harrison added two hits, scored one run and drove in another and robbed Wilson Ramos of extra bases with a diving catch in right field.

Ian Desmond provided all the offense for the Nationals with a solo homer in the fourth as Washington was 0-for-8 with runners in scoring position and left 10 men on base. Blake Treinen (0-2) took the tough-luck loss in his second career start, allowing two runs on four hits and five walks over 5 2/3 innings.

Treinin's control problems caught up to him in the third as he issued a pair of walks and a single to load the bases, then hit McCutchen with a first-pitch slider to force home the game's first run. The Nationals evened it at 1 when Desmond jumped on a 2-0 sinker from Volquez to lead off the fourth with his team-leading eighth home run.

Harrison drew a leadoff walk in the fifth and scored on McCutchen's single to center, and the Pirates tacked on an insurance run in the eighth when Chris Stewart doubled and came around on Harrison's base hit. The Nationals left the bases loaded in the eighth and had two on in the ninth when McCutchen charged in and made a sliding grab on Anthony Rendon's sinking liner to preserve the win.

GAME NOTEBOOK: The Pirates designated LHP Wandy Rodriguez for assignment and activated C Russell Martin from the disabled list. RHP Brandon Cumpton is in line to claim Rodriguez's spot in the rotation and start Monday against the New York Mets. … Pittsburgh LHP Tony Watson worked out of a bases-loaded jam in the eighth and has pitched 13 consecutive scoreless innings over his last 12 appearances. … The Nationals dropped to 4-22 when scoring three or fewer runs.