The titanic battle between the two sides never materialized as a fired-up Cavs surged into a 57-42 lead at half-time.
James was superb as Cleveland improved to 51-27, one game clear of second-placed Boston, who fell to 50-28 following the defeat.
Crucially, the win completed a 3-1 season series for Cleveland over the Celtics, meaning the Cavs would win the head-to-head tiebreaker in the event of the two teams finishing regular season level.
The victory also gives the Cavs a useful psychological edge over the Celtics as the two teams gear up for the postseason.
All of Cleveland's heavy hitters delivered performances to silence the home crowd in Boston. Kevin Love finished with 15 points and 16 rebounds while Kyrie Irving chipped in with 19 points.
A second half points spree proved to be the foundation of the Cavs success, with 38 points helping ensure a 15-point cushion at halftime.
Another one-sided quarter in the third saw Cleveland race away to lead 90-66 with the Celtics powerless to halt the slide.
Isaiah Thomas led Boston's scorers with with 26 points.
Impressively, Cleveland's win on the road came after a 122-102 victory in Orlando on Tuesday.
However, there was a trace of weariness as Cleveland overwhelmed Boston when they clicked into gear after trailing 20-19 at the end of the first quarter.
Cleveland also managed to win without the services of Tristan Thompson, who did not travel after spraining his thumb against Orlando.
source: news.abs-cbn.com
