The Cardinals–Mets rivalry is a Major League Baseball (MLB) National League rivalry played between the St. Louis Cardinals and the New York Mets. This rivalry was initially an intradivisional affair as both teams played in the National League East from to , before becoming an intraleague rivalry after the Cardinals moved to the National League Central in . The rivalry became very prominent in the 1980s as both teams contended for first place in the division; between and either the Cardinals or the Mets finished first in the NL East, with each team winning two division titles. Since the Cardinals left the NL East, however, the rivalry faded from prominence, though the two teams have since met in the postseason twice, in the and National League Championship Series.
History
The Cardinals were already established in the National League when the Mets joined the league as an expansion team in . The Mets' first-ever game as a Major League franchise came on April 11, 1962, against the Cardinals. En route to a 120-loss campaign in their inaugural season, New York lost 11–4 to St. Louis at Sportsman's Park (then Busch Stadium). It took the Mets seven years before engineering their first winning season, which they achieved in when they won 100 games and went on to win the 1969 World Series against the Baltimore Orioles for their first championship. Along the way, the "Miracle Mets" ended the two-year pennant reign of the Cardinals at Shea Stadium on September 24, 1969, winning the newly established National League East division title with a 6–0 victory behind a four-hit shutout performance from pitcher Gary Gentry and two home runs from midseason addition Donn Clendenon.
In , the Mets edged the Cardinals by 1½ games (New York went 82–79 while St. Louis finished 81–81) to clinch their second National League East title, before losing to the Oakland Athletics in seven games of the 1973 World Series. Other than that, neither team factored into the division race for much of the 1970s, taking a backseat to either the Philadelphia Phillies or the Pittsburgh Pirates winning the division during the decade. However, the two teams played in one of the longest games in baseball history, a 25-inning marathon won by the Cardinals on September 11, 1974, at Shea Stadium. In that game, Ken Reitz tied the game 3–3 in the ninth inning with a home run off Mets pitcher Jerry Koosman, and the two teams staged 15 innings of scoreless baseball until Bake McBride scored the winning run following an errant pickoff throw from Mets reliever Hank Webb.
The 1980s marked the emergence of both teams into contenders, and along the way, intensified the rivalry. The Cardinals first returned to prominence in , winning the World Series over the Milwaukee Brewers thanks to their Whiteyball speed-oriented offense led by manager Whitey Herzog and stars such as Ozzie Smith and Willie McGee. However, a big trade involving the two teams in would soon turn the Mets into contenders.
On June 15, 1983, the Cardinals traded National League MVP Keith Hernandez to the Mets in exchange for Neil Allen and Rick Ownbey. Along with the additions of Darryl Strawberry, Dwight Gooden and Gary Carter, the Hernandez trade signaled a change of fortunes for the once-moribund Mets, and by , they emerged as a strong threat to the division-contending Cardinals.
During the 1985 season, the Mets and Cardinals faced off in some memorable encounters. On Opening Day, Gary Carter blasted a 10th inning walk-off home run off Neil Allen to secure a 6–5 win for the Mets. Later in the year, both teams faced off in two three-game series amid a heated division race. On September 12, the Mets temporarily captured first place after defeating the Cardinals 7–6 on a walk-off single from Keith Hernandez. However, the Cardinals eventually won the division title, helped by winning two of three games from the Mets during a series at Busch Memorial Stadium from October 1 to 3. By the end of the season, the Cardinals won 101 games to the Mets' 98, but they went on to lose in the I-70 World Series to the Kansas City Royals.