(SportsNetwork.com) - Tanner Roark tries to avoid a fourth straight losing start on Thursday night as the National League East-leading Washington Nationals open a four-game series with the New York Mets.

Roark is 12-10 with a 2.97 earned run average this year, but is coming off a 3-1 setback to Philadelphia on Saturday. He gave up all three runs on six hits and a walk in six innings of work, striking out eight.

The right-hander is unbeaten versus the Mets, going 3-0 with a 3.10 ERA in four meetings with three starts. He has held New York to four runs over 11 innings in a pair of winning starts this year.

Washington came out of a three-game set versus Atlanta leading the Braves by eight games for first place in the NL East. The Nats won the first two games of the set, but lost Wednesday's finale 6-2, leaving them with a magic number of 10 to clinch the division.

Stephen Strasburg went six innings for Washington, giving up three runs on seven hits and no walks. He struck out eight and lost for the first time in his last six starts.

Nationals manager Matt Williams said "everything's the same at this point" in regards to how his team is approaching its games.

"We're done this series," he said. "We're going into New York against a team with good starting pitching and a power bullpen, so it doesn't get any easier from here."

The Mets have won seven of their last eight games, winning the last two of a three-game sweep of Colorado by shutout. That includes a 2-0 win on Wednesday that saw Rafael Montero throw scoreless ball into the sixth inning to earn his first career victory.

Montero walked four and allowed three hits while fanning seven over his 5 1/3- inning outing. Four relievers combined to complete the four-hit shutout, with Jenrry Mejia shutting the door in the ninth to earn his 25th save.

Eric Young, Jr. totaled three hits and drove in a run for the Mets, who are hanging around in the playoff race as they sit 5 1/2 games out of a wild card spot.

"I'm confident in my ability," said Young. "I know I can play at this level, it's just a matter of getting out there."

Getting out there tonight for the Mets will b 41-year-old Bartolo Colon, who is coming off a 14-5 win over Cincinnati on Friday.

Colon did his part to back the offensive output by holding the Reds to just two runs on seven hits over seven innings. That improved the right-hander to 13-11 this year with a 3.96 ERA.

Colon is 2-3 with a 2.13 ERA in five lifetime meetings with the Nationals, including a loss Aug. 13 despite giving up only two runs -- one earned -- over seven innings.

Washington has own five straight and 15 of its past 17 versus the Mets overall and 11 straight at New York's Citi Field.