The St. Louis Cardinals won their first National League Pennant in 18 years yesterday, with an 11-5 win over the New York Mets. The Cardinals will meet the American League champion New York Yankees in the World Series starting Wednesday. The Yankees clinched the American League title Saturday by beating Cleveland.

The Cardinals got four shutout innings of relief pitching from Bob Gibson and Barney Schultz, but needed three-run innings to overhaul the pesky Mets, who had taken an early 3-2 lead. Home runs by Bill White and Curt Flood helped pile up insurance runs for the Cards.

The Cardinals went into the day tied with Cincinnati for first place, with Philadelphia a game behind. The Reds lost, 10-0, to Philadelphia yesterday, setting the stage for a three-way tie for the pennant had St. Louis lost.

In another development, the San Francisco Giants fired manager Alvin Dark at the Conclusion of their season yesterday. Coach Herman Franks was named Dark's successor.

The Giants closed out their season by dropping two straight to the Cubs to finish three games back of the Cards in fourth place. Dark had been rumored on then outs for most of the season.