WASHINGTON -- In a matchup between the National League's only 12-game winners, Washington's Gio Gonzalez didn't hold up his end against New York's R.A. Dickey.

The Nationals' All-Star left-hander was rocked by the Mets in his worst outing of the season, a 9-5 loss to New York on Thursday.

Gonzalez (12-5) hadn't allowed more than three runs in any of his previous eight starts at Nationals Park while going 5-2 with a 2.31 ERA.

But after Andres Torres beat out an infield hit with one out in the first inning, David Wright sent Gonzalez's fastball over the left field fence.

Ike Davis led off the New York second with a home run to center as the Mets hitters followed manager Terry Collins' advice about being less patient in hopes of ending their season-high six-game losing streak.

"They were swinging aggressively and going after me right off the back," Gonzalez said.

"A good team like that, the way they swing the bat, if you leave anything up there, they're gonna make you pay for it. I learned firsthand about that."

The afternoon never improved for Gonzalez, who allowed two runs in the third on a double-play grounder and a single by Davis. With one out and a runner on second in the fourth, Washington manager Davey Johnson summoned Craig Stammen to relieve Gonzalez, who left the game trailing 5-1.

"I'm not going to let him get beat up," Johnson said.

Gonzalez threw just 37 of his 68 pitches for strikes.

"Command's a big key for him and it was one of those days where he didn't have his best stuff either," Johnson said. "He wasn't real sharp. I didn't want to keep him out there to save my bullpen. I want to save him. Throwing 20, 30 more pitches in a losing cause. What's the use?"

Stammen, who came in with a 1.66 ERA, allowed a run-scoring single to Ruben Tejada and walked Torres before Wright hit his second homer of the game to make it 9-1.

Ryan Zimmerman homered in the first, his 11th of the year and his eighth in his past 21 games. Mark DeRosa doubled and scored on Danny Espinosa's single in the sixth for Washington's second run.

Michael Morse doubled home pinch hitter Ian Desmond and scored on Wright's throwing error in the eighth. DeRosa scored on Roger Bernandina's infield hit in the ninth to close the scoring.

Notes

• The Nationals designated veteran outfielder Rick Ankiel for assignment and activated Drew Storen from the disabled list where the 2011 closer had been all season following elbow surgery. Ankiel was hitting just .228. Storen pitched a scoreless ninth on Thursday and was heartened by the ovation he received upon entering the game.
• Washington put Jhonatan Solano (oblique) on the 15-day DL and promoted fellow backup catcher Sandy Leon from Double-A Harrisburg. Leon's single in the seventh was his first major league hit.
• The NL East-leading Nationals play host to the second-place Atlanta Braves for a four-game series starting on Friday that includes a day-night doubleheader on Saturday. All-Star right hander Stephen Strasburg (10-4, 2.66) starts Friday against Atlanta's Tommy Hanson (10-5, 4.02).