Ilgauskas set a franchise record for most games played with the team, breaking the mark held by Cleveland General Manager Danny Ferry.
He came off the bench to pace his team in scoring while both LeBron James and Shaquille O'Neal had 12 points. O'Neal faced the Suns for the first time since they dealt him to the Cavaliers during the summer.
Channing Frye scored 22 in leading the Suns, who were held to their lowest point total of the season. Their previous low had been the 99 points they produced in a loss on Tuesday to New York.
Phoenix has dropped back-to-back games for the first time this season.
Cleveland went on an 11-0 run late in the first period en route to a 57-29 halftime advantage. The Cavaliers have defeated the Suns three straight times after losing 15 of their previous 18 meetings.