"It's been a while. I got a little excited out there," Detwiler said. "I was a little amped out there."
Ivan Nova turned in a strong start for the Yankees, firing three scoreless, hitless innings. His control was superb in his second outing of the spring, as he threw 31 of 35 pitches for strikes, recording four strikeouts.
"I was trying to attack the strike zone, trying not to walk anybody," Nova said. "You try to eliminate that here, not to carry that over, and then try to make adjustments. You try to be on a good roll for the start of the year."
New closer David Robertson made his spring debut and, after hitting a batter, induced a double play and a flyout. Walters put the Nats on the board in the fifth, connecting for a solo homer to center field off Shawn Kelley. The homer was Walters' first of the spring.
Washington added a run in the sixth when Derek Jeter committed an error on Danny Espinosa's grounder up the middle, allowing Eury Perez to score.
The Yankees welcomed Hall of Fame quarterback Joe Namath into the dugout as a co-manager for the day. Namath, in town for a promotional appearance, threw a ceremonial first pitch to Jeter before spending most of the game by Joe Girardi's side.
Up next: Jacoby Ellsbury and Carlos Beltran are scheduled to be in the lineup on Tuesday when the Yankees play their first night game of the spring, hosting the Orioles in a 7:05 ET contest at George M. Steinbrenner Field. David Phelps makes his second start of the spring, with Wei-Yin Chen drawing the call for Baltimore.
Bryan Hoch is a reporter for MLB.com. Follow him on Twitter @bryanhoch and read his MLBlog, Bombers Beat. This story was not subject to the approval of Major League Baseball or its clubs.