"I came here to win, and we're [4 ½] games out of being out of the playoffs, which is unacceptable," Stoudemire said after the Cleveland Cavaliers cruised to a 127-94 win over the Mavs at the American Airlines Center. "This is something we can't accept. We've got to find a way to refocus. We've got to key into the details of the game of basketball.
"We can't cheat the game. We can't screw around in shootarounds and practices and joke around all the time and figure we're going to win games. This is the pros. It's the highest level of basketball. We've got to act that way."
The Mavs are 5-6 since the post-All-Star break arrival of Stoudemire, who selected Dallas over other suitors after receiving a buyout from the New York Knicks because he believed the Mavs presented him the best opportunity to chase a championship.
At 41-25, the Mavs have slipped to seventh place in the Western Conference. The rout by the Cavs was the third time the Mavs have lost by at least 15 points in the past six days, as they were blown out by the Portland Trail Blazers and Golden State Warriors on their recent road trip.
Stoudemire, a six-time All-Star in his 13th NBA season, has readily accepted a role as a reserve center/forward for the Mavs and been effective in the role, averaging 11.4 points and 3.5 rebounds in 17.5 minutes per game.
Stoudemire will not accept a lack of competitiveness from the Mavs, however.
"We didn't come out with the aggressiveness or determination or focus that we needed," said Stoudemire, who had 15 points and three rebounds in 20 minutes during Tuesday's loss. "We didn't compete. We're not playing like champions, and they took advantage of that.
"We've got to pay more attention to detail. We can't be making minor mistakes. We made mistakes that second-year players or rookie players make in this league. We're a veteran team. Guys are 13, 14, 16 years in this league. We should know better than that.
"We should be a much better team than what we showed out there. This is a team that's competing for a championship that we played against. We should have stepped up to the challenge of competing with these guys and we backed down."
Coach Rick Carlisle said he was "sick to his stomach" about Dallas' performance against Cleveland, blaming bad coaching for the Mavs' many mental breakdowns and concentration lapses.
The Mavs had a five-point lead over the Cavs after the first quarter and fell apart. Dallas allowed 41 points in the second quarter and 101 points in the final three frames.
"Well, we're going to find out what we're made of from here," Carlisle said. "This is the lowest point we've been at. When you get to this point, everyone has to come together."
The Mavs have been mediocre for more than two months, going 15-15 since Jan. 7.
Dallas struggled with implementing poor-shooting point guard Rajon Rondo into the offense after making a blockbuster trade with the Boston Celtics on Dec. 18 to acquire him. Face of the franchise Dirk Nowitzki is trying to fight through one of the worst shooting slumps of his career. The Mavs are dealing with injuries to center and emotional leader Tyson Chandler, who is playing with a sore hip, and key reserves Al-Farouq Aminu (shoulder) and Devin Harris (hand).
Nevertheless, Stoudemire expressed optimism that the Mavs can still be the team he envisioned joining when he made his decision to come to Dallas.
"Absolutely," Stoudemire said. "We've got the right personnel. We've got enough veteran leadership on this team to compete. We've just got to have that mindset to want to step up and truly compete. You want to play against the top players in this league. You want to show them that you've got what it takes to win. Tonight, we didn't do that."