The Mets had a great chance to take sole possession of the division lead in the series opener Tuesday night, but their makeshift bullpen - missing an ailing Wagner - blew a three-run lead for Johan Santana in the ninth inning of an 8-6 loss.
Wagner declared himself available Wednesday after testing his sore left shoulder before the game by playing long toss from about 250 feet and throwing off a bullpen mound.
The All-Star entered in the ninth and got three quick outs for his 25th save in 31 chances, securing New York's eighth victory in nine home games.
The series finale is Thursday, with Jamie Moyer pitching for the Phillies against Oliver Perez.
With the score tied 3-all, Damion Easley opened the sixth with the second of his three infield singles before Brian Schneider also singled against Ryan Madson (2-1).
Maine struck out trying to bunt, but Reyes drove Madson's next pitch to right for his 11th homer. He raised his right index finger high as he trotted from first to second.
Maine (9-7) gave up consecutive homers to Shane Victorino and Geoff Jenkins in the second, but kept Philadelphia in check most of the way. Jimmy Rollins tied it at 3 with an RBI double in the fifth.
Maine pitched only 19 innings over his previous four starts, going 0-2. He yielded six hits Wednesday, striking out five and walking two.
Scott Schoeneweis and Joe Smith combined for a scoreless eighth.
Hoping to find his form, Myers made four starts in the minors before returning to the rotation Wednesday for his first major league outing since June 27. He entered 3-9 with a 5.84 ERA and said recently he realized he needs to use his fastball more and pitch more aggressively.
Still, the 27-year-old right-hander struggled with his command all game. He walked four straight batters in the first inning as frustrated Phillies manager Charlie Manuel watched helplessly, chomping on his gum while leaning over the dugout railing.
Marlon Anderson made it 2-0 with an RBI groundout.
Maine coughed up the lead right away, serving up the homers to Victorino and Jenkins with two outs in the second. Victorino connected Tuesday off Santana.
Myers loaded the bases in the third on a walk, a hit batsman and Carlos Beltran's single. Easley's run-scoring infield single with two outs put New York ahead 3-2.
Philadelphia tied it on Rollins' fifth-inning double, but Maine limited the damage by retiring Chase Utley on a popup and striking out Pat Burrell.
Myers walked five in five innings, throwing 49 strikes and 46 balls. He allowed three runs and three hits.
