A missed third-strike call gave Pittsburgh a second chance, and Jacob Stallings took advantage with a walkoff single to push the Pirates to a 6-5, 12-inning win over Washington on Friday.
The Nationals (89-64) had a chance to close out a win in the ninth, but closer Mark Melancon, formerly of the Pirates, gave up a game-tying two-out double to Sean Rodriguez.
It was the first blown save as a Nat for Melancon (42 saves, 1.76 ERA, 0.95 WHIP).
Yusmeiro Petit (3-5, 4.01 ERA, 1.29 WHIP) gave up the game-winning hit to Stallings in the 12th.
Danny Espinosa (23) and Wilson Ramos (22) each homered for Washington, whose magic number to clinch the NL East division title remains at two.