Willie Mays bid adieu to baseball last night as the Mets honored him with pregame ceremonies and a 2-1 victory over the Montreal Expos. The win boosted the Mets' lead in the wild National League East race to a game and a half over the sagging Pittsburgh Pirates.

The Pirates lost their 10th game in 21 contests under new manager Danny Murtaugh, dropping a 2-1 decision to the Philadelphia Phillies. Steve Carlton hurled a five hitter against the Bucs while Mike Anderson and Bill Robinson provided the only offense needed with solo homers in the second and sixth innings.

Carlton had the shutout going into the eighth when Dave Cash tripled and came home on Gene Clines's ground out for the Pirates only tally. Pirate starter Jim Rooker took the loss.

In other baseball action in the American League, the Boston Red Sox picked up a 3-2 victory over the Cleveland Indians as Orlando Cepeda drilled a three-run homer, his 20th of the season.

The Sox, whose only struggle now is to stay ahead of the Detroit Tigers and hold onto second place, started the rally as Tommy Harper singled, and Carl Yastrzemski was given an international walk. This set the stage for Cepeda's game-winning home run.

Roger Moret, Boston's hot young pitcher, picked up his 12th victory against 2 losses with relief help from Bob Bolin in the eighth inning. Tom Timmerman, 8-8, took the loss. Dave Duncan and Walt Williams accounted for the Indians' only runs with homers in the fourth and seventh innings.