As Boston beat Los Angeles Tuesday night in game six of the NBA finals by 39 points: 131 to 92.
The Celtics are the NBA champions for the 17th time in franchise history, and the first time in 22 years.
The 39 point win is the the largest margin of victory in a clinching game ever.
The previous record was 33 points, set in 1965 by the Celtics over the Lakers.
Kevin Garnett and Ray Allen each scored 26 points for Boston. Paul Pierce has spent his entire career with Boston, and was named the MVP of the finals.
Pierce fittingly scored 17 points Tuesday, one for each of the championship banners that will hang in the Garden next season.
The Celtics win the series four games to two.