Salvador Perez drove in the tiebreaking run in the eighth and the Kansas City Royals ended their seven-games losing streak on Sunday, rebounding for a 6-4 victory after blowing a 4-0 lead against Washington.
With two out and a runner on first and the game tied 4-all in the eighth, Billy Butler hit a hard grounder that first baseman Adam LaRoche knocked down.
The ball rolled several feet to his right and when Stammen was late to cover the bag, the slow-running Butler kept the inning going by chugging to first with an infield single.
Stammen then walked Mike Moustakas on fourth pitches and Perez hit a hard grounder to shortstop Ian Desmond.
He bobbled momentarily and his throw to third was late, allowing the tiebreaking run to cross the plate on a fielder's choice before David Lough's RBI single made it 6-4.
Kelvin Herrera (5-6) pitched 1 1-3 innings of relief for only the Royals' third victory in 13 games.
Craig Stammen (7-6) took the loss and was part of a shaky defense that led to the Nationals' first loss in six road outings.
Greg Holland pitched the ninth for his 35th save in 37 opportunities, giving up two singles but striking out the side.
Stammen went one inning, gave up two hits and two earned runs.