WASHINGTON -- Call John Lannan the stopper. On Tuesday night, he helped the Nationals break their six-game losing streak by pitching a complete-game shutout in a 4-0 victory over the Mets at Nationals Park.

Lannan joins Pedro Astacio (Aug. 15, 2006) and John Patterson (Aug. 4, 2005) as the only Nationals hurlers to hold opponents scoreless in a complete-game win.

It was Lannan's second complete game of the season. The first one also came against the Mets on June 6 at Nationals Park.

It was a game that everything worked well for Washington. It received great pitching and defense and timely hitting.

After Fernando Tatis grounded out to second baseman Alberto Gonzalez to end the game, Lannan took the ball. He didn't keep it for himself. He gave the ball to Jim Riggleman, who picked up his first win as the interim manager of the Nationals.

"Jim said, 'Good job today. That's what we are talking about.'" Lannan recalled. "Tonight, everything went right -- defense, pitched well and we got key hits. That's the way it happens. You have to have a little bit of luck and the hard work is going to pay off. It's not going to happen just like that."

It's coming to the point where Riggleman and the Nationals are expecting Lannan to have quality starts every fifth day.

"John was so outstanding tonight that he made it easy for myself and my staff," Riggleman said. "John works fast, throws strikes -- classic stuff that has been taught from day one. He is a polished guy. He is in his [early] 20s. He pitches like a real seasoned veteran. He knows the role of being the lead guy on our staff. We all feel good when he is out there."

Lannan was never in any serious trouble in the game. In fact, the Mets, who collected seven singles in the game, never had a baserunner get past second base. Lannan induced 17 ground-ball outs and had 23 first-pitch strikes.

"I think he commands his off-speed [pitches] just like any good pitcher, and he constantly pounds the strike zone," Mets manager Jerry Manuel said. "In hitters' counts, he sinks it. It looks like a fastball, but it sinks and gets you to hit it into the ground. We fell into that trap."

Lannan acknowledged that he didn't face the same Mets team he is used to seeing in the batter's box. Their best hitters -- including Carlos Beltran and Carlos Delgado -- are on the disabled list. Instead the right-hander was facing the likes of Tatis, Angel Pagan and Jeff Francoeur.

"They are still a great hitting team. I just face them so much," Lannan said. "I usually do a scouting report where I look at video and stuff. In this scouting report, I basically did it from memory.

"I'm know I'm a ground-ball pitcher. I pitch to contact. I'm not a strikeout pitcher. I just have to keep the walks down and make sure you keep the hitters off balance. I was working in and out today. It wasn't one sided like it was a couple of starts ago. That was the key for me today -- keeping the hitters off balance and keeping the ball in and out."

Lannan received defensive help from center fielder Nyjer Morgan in the third and ninth innings. In the third, the Mets had runners on first and second and two outs, when David Wright hit a fly ball to deep left-center field. Morgan ran after the ball and made a leaping catch near the wall to end the inning.

Six innings later, Luis Castillo led off and hit another deep fly ball to center field. It looked like it would go over Morgan's head. Morgan, however, made a nice backhanded catch for the first out.

Morgan said he likes to make catches for Lannan, because he keeps the fielders on their toes.

"We feed right into that tempo," Morgan said. "Nobody was really caught off-guard out there. Everybody was heads-up, because he kept us in the game.

Washington gave Lannan run support against Mets left-hander Oliver Perez in the fourth and fifth innings. Alberto Gonzalez hit a sacrifice fly to drive in Ryan Zimmerman in the fourth. Adam Dunn then came home on a single by Wil Nieves.

In the fifth, Dunn singled to right field to drive in Morgan. Josh Willingham followed with a sacrifice fly to bring home Zimmerman.

"We had some good at-bats against [Perez]," Riggleman said. "We got some walks. I was impressed by Oliver. A couple of times he threw some breaking balls. Now and then, he reached back and threw some fastballs. He is going to be a tough guy to contend with throughout the rest of the year. I don't think people have seen the best of him yet this year."