Gee (1-0) allowed just one run on two hits in seven spectacular innings, walking three and fanning four while adding an RBI single in his first at-bat for the Mets, who came into Tuesday with six losses in eight games.
The 24-year-old rookie did his best impression of the man he replaced, Johan Santana, who had his start skipped due to a pectoral strain. Ike Davis added a three-run homer in the win.
Willie Harris' homer broke up the no-hit bid, as the Nats failed again in their attempt to win four straight games this season. Washington fell to 0-7 this season after winning three consecutive contests.
The Nationals' starter also made his major league debut, albeit a less successful one. Cuban Yuneski Maya (0-1) gave up four runs on five hits and two walks in five innings.
The Mets used one swing of the bat to jump out into the lead early. Luis Hernandez singled with one out in the first inning, and Carlos Beltran followed with another base hit. Davis put New York ahead by three with his 18th home run of the year -- a shot to right.
Gee helped his own cause in his first at-bat in the second. Ruben Tejada laced a one-out double, and Gee followed with an RBI base hit to right field for a 4-0 margin.
Meanwhile, Gee was nearly flawless. He retired the first seven batters he faced until a walk to Wilson Ramos. Another seven consecutive outs followed for the rookie, before Danny Espinosa drew a two-out walk in the fifth.
Gee carried his no-hitter into the sixth, but it was quickly spoiled by Harris' leadoff homer to left. The Nationals, though, couldn't manage any more offense in the inning.
After Gee pitched a scoreless seventh, Pedro Feliciano and Bobby Parnell combined to get through the eighth without allowing a run.
Hisanori Takahashi came on for the save and allowed singles to both Ryan Zimmerman and pinch-hitterAlberto Gonzalez to put runners on the corners with one out. Pinch-hitter Ivan Rodriguez, though, grounded into a game-ending 6-4-3 double play.
Takahashi earned his fourth save.
The last time two starting pitchers both made their major league debut in the same game was Detroit's Rick Porcello and Toronto's Ricky Romero on April 4, 2009...This is the first instance of two starting pitchers making their major league debut in Washington since September 17, 1909...The Nationals lead the season series, 8-6.