"We came out very focused," Stoudemire said. "We've been playing well the last seven games, except for some little snippets against Portland. We came out with the intensity we showed in that five-game winning streak."
Rudy Gay led Memphis with 21 points and Zach Randolph had 18 points and 15 rebounds. O.J. Mayo and Sam Young, added 15 points apiece. Marc Gasol had 11 points and 12 rebound, and Mike Conley had 10 points and 11 assists.
The Grizzlies lost their fifth straight. Memphis was in the Western Conference's seventh playoff spot less than a month ago, but is now watching its postseason hopes dwindle.
"You've got to forget about what's going on," said guard Mike Conley (10 points, 11 assists). "We're sliding a little bit; having a tough stretch. A little bit of adversity. But we've got to learn how to fight through this."
Phoenix built the lead to as many as 21 in the second half, and Memphis never cut the advantage under double digits after that.
The Suns dominated in the paint, outscoring Memphis 58-32 and shooting 50 percent from the field. The Grizzlies made 36 percent of their shots.
"When [Richardson] plays good for us, we're really, really hard to beat," Suns coach Alvin Gentry said. "If he gets 20, 25 points, we very seldom ever lose. He's a key, key guy for us."
As for the Grizzlies, they struggled to find a rhythm while trying to shake off the rust from a six-day layoff. Randolph played in the All-Star Game, while Mayo and Gasol participated in the All-Star Rookie Challenge as part of the second-year team.
"Coming back is always one of the tough things for us," Gay said. "Always has been. We only had three people participating. Everybody else is basically on vacation."
Memphis' Marcus Williams banked in a desperation shot from 66 feet at the end of the first quarter to give Memphis a 30-27 lead.
Memphis needed the long-range shot because the Grizzlies struggled around the basket, missing easy shots and failing to convert layups.
And Gasol made only one of his eight free throws in the first half as Phoenix built a 14-point lead.
The Suns were up 63-55 at halftime behind 15 points from Lopez and 13 more from Richardson.
Gay had 15 for Memphis.
The Phoenix lead grew to 18 with a rally to open the second half, and eventually extend the advantage to 21 before carrying an 87-74 lead into the fourth quarter.
Phoenix is now in the sixth spot, but only a game out in the loss column to Oklahoma City and Dallas.
"I knew this was a big game for us," Richardson said. "The second half of the season with 29 games left. In the Western Conference every game counts."
The rumored trade of Stoudemire to the Cleveland Cavaliers drew pregame conversation. The Suns forward said he didn't know any more than anyone else about it, and was just waiting to see what happened before Thursday's trade deadline. "I don't know if it is a distraction, but obviously, I think anybody would be kidding themselves if they said it didn't have some effect on an individual," Suns coach Alvin Gentry said, later adding: "As long as he's here and on our team, we'll continue to play him. If something happens and he's traded, then obviously, we'll have to evaluate our style of play." In the second quarter, Grizz, the Memphis mascot, walked to the Suns bench and presented Nash with a paper torch in honor of the Phoenix guard's participation in the opening ceremonies of the Winter Olympics. Nash politely acknowledged the crowd's applause. Gay passed Bryant Reeves for fourth place on the Grizzlies all-time scoring list in the second quarter. Pau Gasol, Shareef Abdur-Rahim and Mike Miller are the only ones still ahead of Gay.