Ryan Zimmerman had a pair of RBI singles and drove in four runs and Jason Marquis tossed six strong innings as the Washington Nationals cruised to an 8-1 triumph over the Pittsburgh Pirates on Sunday.

Adam Dunn homered and drove in two and Ian Desmond added an RBI single for Washington (59-78), which posted its fifth win in six meetings against Pittsburgh this season.

Nyjer Morgan had a single and scored twice on Sunday. The speedy outfielder is appealing his suspension from Major League Baseball following numerous events over the past two weeks - including his actions which ignited a melee against the Florida Marlins on Wednesday.

Marquis (2-7) cruised to his second consecutive win after being staked to an early lead. The 32-year-old right-hander allowed one run and six hits in this one.

Rookie Pedro Alvarez launched a solo homer and Neil Walker had three hits for Pittsburgh (45-91).

Charlie Morton (1-11) permitted six runs and eight hits in 3 2/3 innings to suffer yet another loss. The 26-year-old right-hander has lost six straight outings - and only pitched at least six innings in two of them.