Gerald Henderson scored nine points in overtime at Atlanta and the Boston Celtics defeated the Hawks, 107-103, last night, a night on which Boston star Larry Bird scored only 10 points all game.

Coupled with Philadelphia's loss at Washington, the result elevated the Celtics into a tie with the 76ers atop the Atlantic Division. Each has won 20 of 25 games. The Bullets come next, 6 1/2 games behind.

Substitute guard Henderson, ending as his team's high scorer with 19 points, made a 16-foot jump shot with 3:59 left in the five-minute overtime to extend a two-point Boston lead to 98-94. He made a 14-footer with 1:16 left for a 102-96 margin after Atlanta's Tree Rollins had made an eight-foot jump shot with 1:32 remaining.

The Hawks got back into contention, 103-101, with 24 seconds to play when Dan Roundfield, who had 19 points for the night, got a three-point field goal. Five seconds later, Roundfield fouled Henderson, who converted the two free throws to restore a four-point advantage.

Dominique Wilkins slam-dunked for the Hawks with 0:11 left but, at :009, Eddie Johnson, who led Atlanta scoring with 23 points, fouled Henderson. He again converted two free throws to end the scoring.

The game went into overtime when Cedric Maxwell of Boston blocked Rory Sparrow's 16-foot jumper with three seconds remaining in regulation.