NEW YORK -- John Lannan pitched 5 2-3 shutout innings in his first start since replacing Stephen Strasburg in Washington's starting rotation, and the Nationals lowered their magic number for clinching a playoff berth to six with a 2-0 win over the punchless New York Mets on Wednesday night.
Ryan Zimmerman homered in the fourth off rookie Matt Harvey (3-5) and Ian Desmond connected off Jon Rauch in the eighth, helping the NL East leaders complete a three-game sweep and close in on the capital's first postseason baseball berth since the original Washington Senators in 1933.
A native of nearby Long Beach, Lannan (3-0) allowed five hits, struck out two and walked one in the slot that opened when the Nationals cut short Strasburg's season by imposing an innings limit to protect his surgically repaired right elbow. Lannan, Washington's opening-day starter in 2009 and 2010, spent most of the season in the minors and asked the Nationals to trade him when he was demoted at the end of spring training.
He once again mastered the Mets, improving to 4-1 with a 1.69 ERA against them in his last five starts. Five relievers finished, with Drew Storen retiring pinch-hitter Daniel Murphy on a game-ending flyout with runners at the corners for his second save. The surging Nationals have won nine of 11 and 12 of 15.
New York finished an 0-6 homestand and dropped to 65-78, falling 13 games under .500 for the first time since finishing 2009 at 70-92. The Mets have lost eight of nine overall.
They also extended their club-record streak of scoring three runs or fewer to 13 straight home games. They have lost 22 of their last 26 in Queens and have just four wins at Citi Field since the All-Star break -- two fewer than the Nationals.
Zimmerman put the Nationals ahead in the fourth with a drive into the left-field seats, extending his hitting streak to 16 games. He also made several sparkling plays with his glove at third.
Washington chased Harvey by loading the bases with no outs in the sixth, but Robert Carson relieved and retired Tyler Moore on a foulout, Kurt Suzuki on an infield fly and Steve Lombardozzi on a flyout.
Lannan left in the bottom half after David Wright singled and stole second, and Lucas Duda walked with two outs. Christian Garcia hit Kelly Shoppach on the left arm with his first pitch, loading the bases, but retired pinch-hitter Ike Davis on an inning-ending flyout.
Washington again loaded the bases with one out in the seventh against Bobby Parnell, but Adam LaRoche grounded into a double play on Justin Hampson's first pitch. Desmond then homered to left on Rauch's third pitch of the eighth, a hanging breaking ball.
Washington cut short Strasburg's season last weekend, wanting to protect the 24-year-old right-hander's arm following ligament-replacement surgery on Sept. 3, 2010.
While the Nationals initially intended to make Wednesday's game his final start of the year, they moved up their timetable because they said the limit was weighing on his mind. Strasburg finished 15-6 with a 3.16 ERA in 28 starts with 197 strikeouts in 159 1-3 innings.
Even with the Expos/Nationals franchise headed toward its first playoff berth since Montreal reached the 1981 NL championship series, Nationals manager Davey Johnson said he won't have any regrets.
"Once you make a decision -- you make the decision based on all the right reasons, and then you don't have to revisit it," he said before the game. "Second guess is a wonderful thing in baseball and everybody has it, but none of them have all the information that I have down here."
Johnson said he might use Strasburg as a pinch-hitter down the stretch. Strasburg is hitting .277 with one homer, four doubles and seven RBIs.
"If I can't use your arm, I'll use your bat," Johnson said. "He's pretty bad now but he's going to get worse because he's going to be chomping."
Johnson said Strasburg keeps asking pitching coach Steve McCatty about what his routine should be.
"Of course, he's been pestering Cat about what he can do," Johnson added. "Can I keep throwing off the mound? No. Can I play catch in the outfield? Yes."
NOTES: Washington has won eight in a row in Queens and 12 of 13. ... Nationals LF Michael Morse missed the game after he was diagnosed with a torn cuff and a bone bruise in his left wrist. ... The Mets scratched Murphy from the starting lineup because of a sore back. Ronny Cedeno took his place at 2B but left in the sixth because of a tight right hamstring. ... Players' association head Michael Weiner, undergoing treatment for a brain tumor, was in the Mets' clubhouse speaking with players before the game. ... The previous big league team to score three runs or fewer in 13 straight home games was Seattle, which did it 16 in a row from Aug. 7 to Sept. 13, 2010, according to STATS LLC.