By GREG MENGELT
Langford, a former New Albany and Indiana University standout, went 1 for 3 from the floor and added two rebounds and a blocked shot in the defeat.
Boston is now 25-25 and in eighth place in the Eastern Conference. It was led by 26 points from Jaylen Brown and 20 from Jayson Tatum.
Atlanta, which improves to 23-25 with his sixth straight victory, got 21 points, nine rebounds and six assists from Trae Young and 21 points and nine boards from John Collins.
Langford and the Celtics go to New Orleans to face the 18-29 Pelicans on Saturday at 6 p.m.