WASHINGTON (AP) The Washington Nationals looked in trouble early. The New York Mets' Noah Syndergaard was in big trouble a couple of innings later.
The Nationals dealt Syndergaard his first loss in more than a month, an 11-4 victory over the Mets on Monday night in the opener of a three-game series between the division rivals.
The Nationals increased their lead over idle Miami to 3 1/2 games in the NL East, while the Mets are four games back.
The Nationals stole six bases, matching their most since the franchise moved to Washington in 2005.
Washington erased the early 4-0 deficit against Syndergaard (8-3), who had won six consecutive decisions and had not lost since May 6. He lasted only three innings, surrendering season-highs in runs (5) and walks (3).
''When you give up four runs early to Syndergaard, most of the time the game is over,'' Nationals manager Dusty Baker said. ''Good thing for us he wasn't as sharp as he usually is, and he had some untimely walks in there.''
Washington starter Joe Ross (7-4) gave up four early runs then retired 11 of his last 12 batters.
Syndergaard was making his first start since leaving a June 22 outing against Kansas City with elbow pain. The right-hander underwent an MRI between starts, but said the elbow wasn't the cause of Monday's shaky performance.
''It felt really good actually, almost felt too good,'' Syndergaard said. ''The first inning I was a little erratic, felt too strong out there not that that's a bad thing but I just wasn't able to locate.''
Syndergaard escaped a no-out, bases loaded jam in the first inning, but wasn't so fortunate in the third. The Nationals scored five runs to erase the 4-0 deficit.
''I don't know if it was shell-shocked but you could tell there were too many good swings,'' Mets manager Terry Collins said. ''He's still throwing 98 to 100 miles per hour but a couple of the sliders they hit - again, no depth to them. I know he throws hard but there's certain nights where you still got to make pitches. Tonight he didn't.''
Washington added five runs over the next two innings against reliever Sean Gilmartin.
Ross allowed the first four hitters to reach in the third inning, prompting a mound visit from Baker. Ross got the next nine batters and didn't allow another runner past first base.
''(Danny Espinosa) said `Hey, Skip's coming out,' and my first thought was `I didn't think there was anyone in the bullpen. Hopefully, I'm not done yet,''' said Ross, who pitched six innings. ''He came out there and had the confidence in me to keep going and work my way through it.''
The Nationals' offense erased the deficit in the third inning, batting around against Syndergaard. Ben Revere had four hits and three steals and Anthony Rendon had three RBIs for Washington, which had its largest scoring output since an 11-4 victory at the Chicago White Sox on June 8.
Washington recalled RHP Rafael Martin, who was 1-3 with a 4.40 ERA and 14 saves at Triple-A Syracuse. Martin pitched a scoreless ninth Monday.
Nationals closer Jonathan Papelbon, on the DL since June 14 with a right intercostal strain, pitched a scoreless inning Monday in a rehabilitation appearance at Single-A Potomac.
Mets OF Brandon Nimmo recorded his first career hit in the second inning. Nimmo, who was playing in his second game, went 2 for 4.
Mets: LHP Steven Matz might not make his scheduled start Wednesday because of elbow discomfort, Collins said. Matz underwent an MRI on Monday in New York and will be re-evaluated Tuesday.
Nationals: RHP Stephen Strasburg underwent an MRI on Monday morning, Baker said. Strasburg was scratched from his last two starts with an upper back strain and was placed on the DL on Sunday.
Mets: Matt Harvey, who owns a 2.25 ERA in five starts since absorbing consecutive losses to Washington, faces the Nationals for the third time this season.
Nationals: Top prospect Lucas Giolito will make his major league debut Tuesday. Giolito, the No. 16 pick in the 2012 draft, is 5-3 with a 3.17 ERA and 72 strikeouts in 71 innings at Double-A Harrisburg.