Houston, TX (Sports Network) - Rob Mackowiak went 2-for-4 with a two-run homer, and John Lannan tossed six strong innings, as Washington staved off a sweep with an 8-3 win over Houston.

Lannan (3-3) gave up just one run on seven hits and one walk, with three strikeouts for the Nationals, who had lost the first two games of this three- game set.

Ryan Zimmerman collected three hits, and Cristian Guzman scored three times and had a pair of hits for the Nationals, who won five of seven games against the Astros last season.

Brandon Backe (2-4) took the loss after allowing four runs on six hits in six innings, though he had three walks to nine strikeouts. Miguel Tejada, Lance Berkman and Carlos Lee each had a pair of hits for the Astros, who had 10 overall but just one for extra bases - a double from Ty Wigginton.

The Nationals took a commanding lead in the later innings. In the sixth, Guzman and Zimmerman led off with consecutive singles, and Nick Johnson walked to load the bases.

Austin Kearns delivered with a liner to center that plated two runs for a 4-1 edge. However, the Nationals' rally petered out from there, as Ronnie Belliard and Mackowiak flied out, and Wil Nieves grounded out to end the threat.

Still, two frames later, Washington's offense put up three more runs.

Kearns walked on a wild pitch from Oscar Villarreal, which also allowed Zimmerman -- who singled, and advanced to third on an error and ground out -- to sprint home.

Two batters later, Mackowiak homered to left to stake the Nationals to a 7-1 lead.

The Astros got two runs back in the home half of the eighth -- An RBI single from Lee scored Tejada, and a groundout from Wigginton with runners at the corners allowed Berkman to go home.

Guzman scored Washington's final run in the ninth, on the same sequence that Johnson grounded into a double play. Jon Rauch pitched a perfect ninth to close out the contest.

Johnson's double in the first inning plated Guzman to gave Washington, which took a 2-0 lead in the third frame on Willie Harris' solo homer.

Houston got a run back in the fourth on Hunter Pence's RBI single.