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Yunesky Maya didn't know for sure whether he'd even be added to the Washington Nationals roster when he arrived at Nationals Park on Saturday. When he left, he'd earned his first major league win.

The Nationals brought Maya to Washington as a back-up plan in case they traded scheduled starter Jason Marquis. When a trade with the Arizona Diamondbacks went through before the game, Maya was officially called up from Triple-A Syracuse and pitched 5 1-3 scoreless innings in a 3-0 victory over the New York Mets.

"Maya showed up, I think like an hour and two minutes before his start, and he went out there and under the circumstances pitched great," said Jayson Werth, who provided the Nationals' offense with a three-run home run in the first inning. "He got the win, and we needed it. We've been reeling a little bit, and it's a step in the right direction."

He walked into the Nationals clubhouse in street clothes about an hour before game time and about 45 minutes before Washington publicly announced the trade. The late notice didn't seem to affect him as he retired the first seven batters and didn't allow a hit until David Wright singled with two outs in the fourth.

"It was a little hard, but in a way I was ready for it," Maya said through an interpreter. "They told me to come up here and I might be able to start. Nothing was for sure, but I was ready."

Maya, who made his major league debut with Washington last season, was making his fourth start of the season and 10th of his career. He entered the game with an 0-4 career record.

Although he ended up with the win, the outing didn't end quite the way he wanted. In the fifth inning, Maya hurt his back on the basepaths trying to avoid a tag. He came back out to the mound for the sixth but gave up consecutive one-out singles to Daniel Murphy and Wright, leading Nationals manager Davey Johnson to bring in reliever Ross Detwiler, who promptly got Angel Pagan to ground into a double play.

After the game Johnson said Maya had strained his oblique muscle and may need to go on the disabled list. Maya, however, said he felt he would be fine and termed his status day to day.

Drew Storen pitched the ninth for his 26th save in 29 chances, although he gave up a walk and two singles, loading the bases with two outs. Pinch-hitter Willie Harris stuck out looking on a slider to end the game.

"The strike-three pitch was a straight-up pitcher's pitch," Harris said. "Good pitch, all I can really say."

Washington grabbed the lead in the first inning. Rick Ankiel led off with a single against R.A. Dickey (5-9) and advanced to third on a sacrifice and wild pitch. Dickey walked Michael Morse to put runners on the corners for Werth, who drove a 3-2 knuckleball deep to center field for his 12th home run of the season.

"If I had three pitches back, we<d still be playing," Dickey said.

New York had perhaps its best offensive chance in the fifth. A pair of two-out singles by Josh Thole and Dickey brought up Jose Reyes with runners on first and second. Reyes hit a ball deep to right-center but Werth caught it on the warning track to end the inning.

The Mets were shutout for the fifth time this season and ended a five-game winning streak.

Washington snapped a six-game losing streak, its longest of the season, on a day when two veterans were traded. In addition to Marquis, utilityman Jerry Hairston Jr. was sent to Milwaukee before the game.

"That's part of baseball, but it's never easy on a ballclub because you have a lot of attachments," Johnson said. "You talk to two guys and tell them they're going somewhere, that's never easy for the manager. But the players responded."

NOTES: The Nationals received OF Erik Komatsu, who was with Double-A Huntsville, from the Brewers for Hairston. Washington recalled OF Brian Bixler from Triple-A Syracuse to fill Hairston's roster spot. ... Storen, who has been the subject of trade rumors, said he hoped he'd stay in Washington. "I know I<ve only been here for about a year and a half, but emotionally, I<ve invested a lot in this," Storen said. ... Wright had two singles, giving him a career-high seven consecutive multihit games. Wright has a hit in all nine games since he returned from the disabled list (lower back stress fracture) on July 22.