Washington took a 1-0 lead in the top of the first on an RBI single by Dmitri Young, but LaRoche hit a two-run double as part of Pittsburgh's six-run second -- and then added a solo home run in the fifth.

Freddy Sanchez and Jack Wilson both had two RBI for the Pirates, who have won four of five against Washington this season.

Winner Tom Gorzelanny (8-4) gave up two earned runs and five hits in 7 1/3 innings, with three walks and six strikeouts.

Ronny Belliard hit a solo homer in the sixth, while Ryan Zimmerman had a run and two hits for the Nationals, who have dropped five in a row.

Loser Jason Bergmann (1-5) gave up six earned runs and eight hits in four innings.