Paul, who has been out since Nov. 7 due to a heel injury that forced him to leave a loss to the Philadelphia 76ers, had four points, four rebounds and four assists in 24 minutes, but it was Boston that rolled, 125-98.
The Suns went 9-5 over the past month with Paul sidelined.
The 37-year-old entered Wednesday averaging 9.5 points and 9.4 assists across 10 games this season. The 9.5 points would easily be the lowest of Paul's career, as he has never averaged less than the 14.7 he posted last season. He's also shooting career-worsts from the field (36.8%) and 3-point line (27.3%).
Boston was without starting center Al Horford, who entered the NBA's health and safety protocols Wednesday. Guard Malcolm Brogdon did play after a non-COVID illness and had 16 points, 5 assists and 3 rebounds in 19 minutes.
The Celtics, who began a six-game road trip with wins in Brooklyn on Sunday and Toronto on Monday, have the NBA's best record at 21-5. Boston next plays Saturday in San Francisco against the Golden State Warriors before a back-to-back in Los Angeles on Monday and Tuesday.