The Suns set a season high in scoring for a quarter with their third-quarter blitz. Phoenix made 13 of its first 15 shots in the second half and finished the third period 17-for-22. The 40 points were the most allowed by Dallas in a quarter this season.
"We got some turnovers, got in the open court, got some easy baskets," Suns coach Terry Porter said. "That just opens everything up."
Dirk Nowitzki scored 19 for Dallas, and Josh Howard had 16 before departing with a sprained left wrist in the third quarter. X-rays were negative.
Amare Stoudemire scored 16 in Phoenix's fourth win in five games. Grant Hill added 10 points, eight in the third quarter, as the Suns shot 63 percent for the night. Steve Nash had nine points and 12 assists.
O'Neal scored 19 in the first half. He was 7-for-7 at the foul line for the game.
"I changed my form -- I went back to my old high school form," he said.
The Mavericks were playing the second game in two nights, just as the Suns were when they lost at Dallas on Dec. 4.
"You never know," Dallas' Jason Terry said when asked if playing back-to-back nights affected his team. "...Against a team like this you've got to have a lot of energy, which we had none tonight."
Howard was injured when he hit the court after going up for a rebound with 9:43 left in the third quarter. He departed in obvious pain cradling his left wrist.
"I got knocked off balance going up for a rebound and came down kind of off-balance and tried to catch myself and all the weight went on my left wrist," Howard said. He said it was similar to an injury he had earlier in the season.
Up 64-58 at the half, the Suns turned it in to a blowout with a 22-4 run, capped by Stoudemire's fast-break basket that made it 86-65 with 5:42 left in the third quarter. Moments later, Hill made a 3-pointer that put Phoenix up 93-69, then Richardson sank a 3 with 47 seconds remaining. Stoudemire punctuated the big quarter with a dunk to put Phoenix ahead 104-77 entering the fourth.
Dallas, coming off a 99-94 home victory over New York on Thursday night, shot 47 percent in the first half to Phoenix's 58 percent, but the Mavericks were 7-of-11 on 3s, including 3-of-3 by Jason Kidd, to stay close. The Mavs were 2-of-9 on 3s in the second half.
Howard scored all 16 of his points in the first half, 14 in the first quarter.
Phoenix's previous highest score was 125 against Milwaukee on Dec. 9 ... The Suns' 52 field goals were their most of the season -- by eight -- and the most allowed by Dallas. ... Phoenix had a 68-18 advantage in points in the paint... The Mavericks had won four of their last five. ... O'Neal went 13-for-13 at the foul line for the Lakers on April 17, 2001. ... Alando Tucker, recently back from the development league, made his first appearance of the season for Phoenix and scored four points.