Sluggish for the first 24 minutes, the Cavs opened the second half with a 12-0 run and sent Phoenix to its 17th loss in 19 games.
Cleveland improved to 2-1 under new coach Tyronn Lue, who took over last week when David Blatt was fired halfway through his second season. The win means Lue and the Cavs' coaching staff will represent the Eastern Conference at the All-Star Game on Feb. 14 in Toronto.
J.R. Smith added 18 points as Cleveland, which led by 28 in the fourth, handed Phoenix its 12th straight loss on the road.
Lue wants the Cavs to play much faster than they did under Blatt, pushing the ball up the floor and running whenever possible to take advantage of their athleticism. It's a work in progress -- Lue said his players need to be in better shape -- and Cleveland struggled trying to find any rhythm for much of the first half.
However, the Cavs, who only led 55-50 at the break, came out flying in the third and quickly pushed their lead to 17.
Love buried a pair of 3-pointers during Cleveland's 12-0 spurt, which was highlighted by Smith taking a long outlet and bouncing a pass high off the backboard to a trailing James, who grabbed it with two hands and dunked to make it 62-50.
Moments later, James snagged an alley-oop pass from Smith and the Cavs eventually built their lead to 16 after three.
The rout was on, allowing Lue to rest James for the entire final quarter. During a late timeout, James laughed and danced near the huddle around Lue as "Super Freak" blared throughout Quicken Loans Arena.