HOUSTON (AP) - Michael Morse homered twice, Jordan Zimmermann matched his career high with 11 strikeouts and the Washington Nationals completed a four-game sweep of the Houston Astros with a 5-0 victory Thursday night.

Morse drove in three runs and extended his hitting streak to a career-best 18 games, the longest active string in the majors after Miami's Jose Reyes was stopped at 26 games earlier in the day. Zimmermann (9-6) pitched six innings of three-hit ball before three relievers finished Washington's seventh shutout of the season.

The NL East-leading Nationals have won six in a row and own baseball's best record at 69-43.

Adam LaRoche drove in a run in the fourth inning before a sacrifice fly by Morse made it 2-0.