The Astros, however, are giving the NL East leaders all they can handle.
Coming off their second straight extra-inning win in Houston, the Nationals again look to add to the Astros' misery Wednesday night in the third of a four-game set.
Although Washington's record is 31 1/2 games better than Houston's, the first two games of this series could have gone either way.
The Nationals (67-43) won Monday's opener 5-4 in 12 innings as Kurt Suzuki's bunt single produced a pair of throwing errors, allowing Roger Bernadina to score the winning run from first. A night later, Danny Espinosa hit a two-run homer in the second inning and had an RBI single in the 12th to break a 2-all tie. The Astros (36-75) had a chance in the bottom of the 12th with runners on first and second and two outs, but Bernadina made a sensational running catch while crashing into the wall to end the game and lift Washington to its fourth win in a row and 14th in 19 games.
"They're holding together and doing a great job, but we need a laugher,'' Nationals manager Davey Johnson said.
The Astros probably could use one even more, but unlike the Nationals, who own a four-game lead over Atlanta in the East, the rest of their season is pretty inconsequential.
Houston is 4-32 since June 28, and 0-11 in extra innings this season.
"We're not winning them, but there is a lot to learn,'' Astros first baseman Brett Wallace said. "We just have keeping building off of that, and eventually those balls will fall.''
The Astros got on the scoreboard first Tuesday on Ben Francisco's two-run, first-inning homer, but managed just four hits the rest of the way.
The extra innings gave Washington's Michael Morse a chance to extend his hitting streak. He took advantage, doubling to start the 12th inning after an 0-for-4 start. Morse is batting .324 during a career-best 16-game streak.
Adam LaRoche, however, was hitless in five at-bats after batting .458 with four homers and 10 RBIs in his previous six games. He is 3 for 4 with a homer against Armando Galarraga (0-1, 5.23 ERA), Houston's probable Wednesday starter.
Galarraga had little luck harnessing his control against Atlanta on Friday, issuing a career-high seven walks while also hitting a batter. Five more Braves reached base via hits over the 5 1-3 innings he pitched. Galarraga allowed only four runs, but suffered a 4-1 loss in his second start after being recalled from Triple-A Oklahoma City on July 28.
This will be his first career appearance against the Nationals, who counter with Gio Gonzalez (13-6, 3.34).
Gonzalez gave up four runs and a season-worst nine hits in a season-high eight innings of a 5-2 loss to Miami on Friday. He also matched a season-best with 10 strikeouts while walking none for only the third time in 22 starts.
The left-hander has only one win in his last five starts, and a 5.14 ERA in his last two outings after yielding two runs or fewer in three of his previous four.
Gonzalez gave up two hits and two walks with eight strikeouts in seven innings of a 1-0 win over Houston on April 17, his lone career start versus the Astros.