Larry Bird scored 40 points and Kevin McHale had nine of his 26 points in the final four minutes last night as the defending champion Celtics rallied for a 126-123 victory over Cleveland in an opening-round game of the National Basketball Association playoffs in Boston.

The Celtics held a 13-point lead with just over four minutes left in the third period, but had to pull out all stops to edge the Cavaliers.

"We had to play the best basketball we could play in the last few minutes to come out with a win," said guard Danny Ainge.

Led by Roy Hinson (24 points), John Bagley (22) and World B. Free (18), Cleveland went ahead, 120-117, with 3 1/2 minutes left.

McHale scored on a base-line pop and a free throw. Bird hit a short fallaway, but Free regained the lead for Cleveland with a layup, 123-122.

McHale made two free throws with 1:27 left and then, after the Cavaliers lost the ball out of bounds, he took a pass from Bird and sank a hook shot over Lonnie Shelton with 24 seconds left.

Edgar Jones missed a three-point attempt. The ball came back to Free but, as time ran out, his three-point attempt bounced off the rim.

"They know how to play down the stretch, we're just learning," said Cleveland Coach George Karl. "I thought we had a good chance to beat them, and I know we can beat them."

The second game of the best of five series will be Saturday in Boston.