Chalmers led the Heat, James broke out to finish it with a flurry and the Heat used a 33-5 run to rout the San Antonio Spurs 103-84 on Sunday night and even the series at one game apiece.
James missed 10 of 13 shots through three quarters and the Heat trailed by a point late in the period before unleashing the lethal brand of basketball that led them to a franchise-record 66 wins this season.
Chalmers finished with 19 points, and James had 17 points, eight rebounds, seven assists and three blocks - the best on Tiago Splitter's dunk attempt - while shooting only 7 of 17 from the field.
For two days following Game 1, the thought was that James needed to do more for his teammates. Turns out, it was Chalmers and the supporting cast who did something for James.
The Heat made 10 of 19 3-pointers and got 13 points from Ray Allen, and 12 points and 10 rebounds from the previously slumping Chris Bosh.
Danny Green made all six shots, including five 3-pointers, and scored 17 points for the Spurs. They host Game 3 on Tuesday night.
Tony Parker had 13 points on 5-of-14 shooting for the Spurs, who were so precise in their 92-88 victory in Game 1 but threw the ball all over the white-surrounded court Sunday, committing 17 turnovers that led to 19 Miami points.
Tim Duncan shot 3 of 13 and finished with nine points and 11 rebounds.