Phoenix was dominant inside against Boston's front line to build an 18-point lead in the first half and never let up, snapping a three-game losing streak.
Steve Nash had 13 points and 10 assists, while Robin Lopez and Mickael Pietrus added 11 points apiece.
Boston, the NBA's top-shooting team, never found a rhythm offensively, shooting 34 percent and making just two of its 18 3-point attempts. Kevin Garnett had 18 points and nine rebounds, but was ejected in the fourth quarter after a below-the-belt shot on Channing Frye.
The incident occurred with Phoenix well ahead, when Garnett went out to challenge a 3-point shot by Frye. Garnett reached out without looking and struck Frye in the groin area, sending him to the floor grimacing.
Frye jumped up and got in Garnett's face and the two had to be separated. After restoring order, the officials took a long look at the play on video and gave two technical fouls to Garnett. Garnett seemed surprised by the call, but walked off after calmly speaking with the officials.
Frye, and Boston forward Kendrick Perkins and guard Nate Robinson also were hit with technical fouls.
The Celtics were having plenty of problems long before that at both ends, coming off a sometimes-rough win over Portland the night before.
Offensively, they couldn't seem to hit anything from the perimeter and limped through a 16-point first quarter.
Boston was even worse defensively, relegated to fouling Lopez and Gortat inside while giving the rest of the Suns one open shot after another. Gortat, who averages 5.9 points, scored 11 in 5 minutes and dropped in his second career 3-pointer at the buzzer to put the Suns up 14.
The Celtics kept missing, the Suns kept hitting and eventually coach Doc Rivers lost his temper, hit with two technical fouls for arguing with referee Steve Javie at 4:33 in the second quarter with Boston trailing 40-25.
It didn't get much better after that.
Boston missed all of its seven 3-pointers in the first half and Ray Allen, one of the best free throw shooters in NBA history, even clanged two from the line as the Suns led 49-35.
The Celtics got more bad news when forward Glen Davis, who averages 12.3 points and 5.3 rebounds as a reserve, sat out the second half with a strained right hamstring.
Phoenix dominated the third quarter and Boston managed a short run in the fourth, but was still down 11 when Garnett was ejected, putting an ugly exclamation on an ugly night.
Notes
The Suns have won three straight over Boston after sweeping the series last season. … The trampoline dunk show between the third and fourth quarters went off without a hitch after a member of the Sun's 'Soul Patrol' put his entire body through the basket Wednesday night against Charlotte.