"Whatever happens is gonna happen, and you guys [the media] can write whatever you want," Detwiler said of the competition. "I know if I go out there and throw well, and I feel good coming out of it, I'll have a good chance for whatever I'm supposed to do. And if I don't, then I don't deserve it."
The Mets' Daisuke Matsuzaka also started for the third time and lasted 3 2/3 innings. He held Washington to one run on three hits, with no walks and four strikeouts.
The Nationals, who were led by Adam LaRoche's three hits, took a quick lead in the first. Denard Span led off by scorching a double to right field. He then stole third and scored on Bryce Harper's groundout.
The Mets tied it up in the fourth, as David Wright singled with one out, moved to second on a passed ball and scored on Josh Satin's double that zipped just past third baseman Zach Walters.
Washington broke the tie in the seventh off top prospect Noah Syndergaard, with some help from the New York defense. LaRoche led off with a pop up that dropped between two fielders in shallow left for a single, and Walters followed with a broken-bat single to center. After both runners advanced on Tyler Moore's infield-fly-rule popout, the infield came in for Danny Espinosa, who hit a ground ball to second base. Anthony Seratelli couldn't come up with it cleanly, and LaRoche scored on the error.
Syndergaard recovered, getting Brian Goodwin to ground out to end the inning. The towering right-hander continued his impressive Spring Training, striking out five batters over 3 2/3 innings.
Seratelli quickly made up for the error with a game-tying RBI single off Manny Delcarmen in the eighth inning. The Mets took the lead in the frame when Kirk Nieuwenhuis walked with the bases loaded, forcing in Omar Quintanilla. The four-run eighth gave the Mets a 5-2 lead.
In the bottom of the frame, the Nats struck back when Brock Peterson launched a three-run homer off Jacob deGrom, tying the game at 5.
However, the scoring didn't end in the eighth. With two outs and the bases loaded in the ninth, Nieuwenhuis knocked a two-run single off right-hander Brian Dupra, scoring Quintanilla and Seratelli to put the Mets up for good.
Up next: Zack Wheeler will continue his preseason tune-up Friday in the Mets' first night game of the spring at Jupiter, Fla. Wheeler hasn't allowed a run in six Grapefruit League innings, with six strikeouts and one walk. He will oppose Marlins right-hander Tom Koehler in the 7:05 p.m. ET game. The game can be heard live on Gameday Audio.