The Nationals went ahead in the eighth inning or later for the fifth time this season, and they improved to 5-2 in games decided by one run. Last night’s triumph was Washington’s second in a row by that margin, and according to Manager Davey Johnson, there’s a consensus in the clubhouse that players expect to win close games.

“I really have confidence in our offense. I really do,” Johnson said.

The results so far have been unmistakable. Washington (10-3) has the best record in the NL by a half game over the Los Angeles Dodgers, who lost last night.

The Nationals are the only team in the NL with 10 wins and one of two in the big leagues with double-digit victories. They have won eight of their past nine and continued their strongest start since going 8-5 to begin the 2005 season.

Nationals catcher Wilson Ramos and teammates celebrate Wednesday’s 3-2 win, the fifth by one run so far. (Jonathan Newton/The Washington Post)

Starting pitching of course has kept the Nationals close, and Jordan Zimmermann was no exception against Houston. The hard-throwing right-hander allowed one run over seven innings, although he still has not logged a win despite an ERA of 1.29.

The starting rotation has a collective ERA of 1.65, and it stands perhaps to improve when Edwin Jackson takes the mound tonight. In his last appearance, Jackson tossed a two-hitter with one walk and nine strikeouts in 4-1 victory over Cincinnati.

“Our pitchers have the mind-set that you can’t get beat if you don’t let them score any,” Johnson said. “That part’s working good.”