April 18

From The Met Wiki

1965: The Mets split a doubleheader with the Giants, losing the first game, 4-1, and winning the second, 7-1. In Game 2, Mets' pitcher Gary Kroll records his first major league win.

1970: Nolan Ryan pitches a one-hitter and strikes out 15 batters in a 7-0 win over the Phillies at Shea Stadium

1971: Gary Gentry pitches a one-hitter in a 5-2 win over the Pirates in the first game of a doubleheader at Shea Stadium.

1984: Wally Backman hits a two-out double in the ninth inning to give the Mets a 5-4 win over the Expos at Shea Stadium.