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Lanky left-hander John Lannan can eclipse his career-best season win total tonight when the Washington Nationals play the Houston game set at Nationals Park.

Washington's Ryan Zimmerman crossed home plate with the winning run in the bottom of the 11th inning after a throwing error by Astros third baseman Jimmy Paredes to give the Nationals a 4-3 win in Friday's opener.

Zimmerman worked a one-out walk against Lucas Harrell (0-1) and Michael Morse followed with a walk to put the winning run at second. Wilton Lopez entered the game to face Jayson Werth, who slapped a grounder to Paredes. Paredes rushed his throw to second and the ball rolled into right field, allowing Zimmerman to score.

Zimmerman added a two-run homer and Chris Marrero chipped in an RBI double for the Nationals, who snapped a two-game skid and won in walkoff fashion for the 12th time this season.

Tyler Clippard (3-0) tossed two innings in relief to earn the win.

Jason Bourgeois picked up three hits and Clint Barmes added two hits and an RBI for the Astros, losers in six of their last seven games.

Lannan, a 6-foot-4, 215-pound native of Long Beach, N.Y., was a nine-game winner in each of his first two major-league seasons in 2008 and 2009, then won eight times in 25 starts with the Nationals last season.

He got to win No. 9 this year in his most recent start on Sept. 5, when he pitched 5 1/3 innings of five-hit, one-run ball on the way to a 7-2 defeat of the Los Angeles Dodgers.

The win snapped a four-start skid for Lannan, who'd been beaten by Philadelphia twice, Arizona and Atlanta since last winning on Aug. 2.

He's 5-6 in 15 home starts overall in 2011 and 3-2 in six career matchups with the Astros to go along with a 4.33 earned run average in 35 1/3 innings.

Houston counters with 32-year-old lefty Wandy Rodriguez, who's won double- digit games in four of seven seasons, including his last three in a row.

The Dominican got to No. 10 this year with a 7-4 defeat of the Pittsburgh Pirates on Aug. 29, when he went seven innings and allowed three runs on four hits with a season-high 13 strikeouts.

He's alternated wins and losses in his last eight decisions, following up the defeat of the Pirates with a 4-0 loss to Milwaukee after allowing six hits and three runs in six innings on Sept. 4.

Rodriguez is 4-1 in his career against the Nationals in eight starts, walking 18 batters and striking out 37 in 47 innings.

The Astros took two of three over the Nationals on July 18-20, but lost three of four in Washington a season ago.