May 21

From The Met Wiki

1972: The Mets defeat the Phillies, 4-3, at Philadelphia. It is the Mets 11th consecutive win.

1978: After falling behind by five runs in the first inning, the Mets come back to defeat the Phillies, 6-5, in 10 innings at Shea Stadium.

2005: The Mets defeat the Yankees, 7-1, at Shea Stadium. Every player in the Mets' starting lineup gets at least one hit in the game.

2010: In his first game after being recalled from Triple-A Buffalo, Elmer Dessens takes the loss as the Mets fall to the Yankees, 2-1.