Dirk Nowitzki had 32 points and 12 rebounds and Josh Howard added 24 and nine as Dallas dominated Phoenix in the fourth quarter en route to a 105-98 win on Sunday.
Reserve Brandon Bass provided all the offense off the bench with 19 points for Dallas, which finished the game on a 27-7 run.
Criticized for their inability to close out games, the Mavericks engineered a remarkable fourth-quarter turnaround fuelled by tough defense at the Phoenix arena.
"We took the ball to the basket, unlike the third quarter. We moved the ball on offense, unlike the third quarter, and it all clicked for us," Dallas coach Avery Johnson said.
"We haven't been able to win these types of games, so it was good that it finally happened."
As a result, Dallas (48-29) is just ahead of the Denver Nuggets (46-30) for the final playoff spot in the West and two games ahead of the Golden State Warriors (46-31), who are lurking in ninth place.
"We are not out of it. We are still trying to work our way up," Howard said. "The guys understand that and we needed a win, I don't know if it is desperation, we just need wins."
The Mavericks, who are just 13-11 since acquiring star point guard Jason Kidd from the New Jersey Nets, picked up just their second win in 13 games against teams with a winning record during that span.
In Seattle, Kevin Durant scored a season-high 37 points and fellow rookie Jeff Green had a season-high 35 as Seattle damaged Denver's playoff hopes, winning 151-147 in double overtime.
Green, whose previous high was 23 points, scored 24 in the second half and overtime. His five quick points to start the second overtime gave the draft-lottery-bound Sonics (18-59) the winning cushion.
Carmelo Anthony, who scored 47 points on Saturday in a loss to Sacramento, led the Nuggets with 38 points. The loss kept the Nuggets in a tie with Golden State for the eighth and final playoff spot in the Western Conference.
In New Orleans, Louisiana, Serbian star Peja Stojakovic and David West each scored 25 points Sunday to spark the New Orleans Hornets past Golden State 108-96 in a key game.
Chris Paul added 16 points for the Hornets, who improved to 54-22 to move atop the Western Conference by two games ahead of the Los Angeles Lakers and San Antonio Spurs, who each clinched a playoff berth with Golden State's loss.
The Warriors, 46-31, dropped half a game behind Denver for the eighth and final playoff spot in the West and put Houston, Phoenix and Utah on the verge of securing playoff berths win one more victory or Golden State defeat.
Monta Ellis led Golden State with 35 points while Baron Davis and Latvian Andris Biedrins each added 17.
In Miami, Rodney Stuckey scored 19 points and Detroit wrapped up the No 2 seed for the Eastern Conference playoffs with its fifth straight win, a 91-75 decision over the Heat. Earl Barron scored 20 points for Miami, which lost its seventh straight.
In Portland, Oregon, Tim Duncan had 27 points and 11 rebounds and San Antonio won its 12th straight against Portland, winning 72-65.
Manu Ginobili's dunk with 1:31 left all but sealed it for the Spurs, who handed the Blazers their fifth consecutive loss.
In Los Angeles, rookie reserve Aaron Brooks scored 18 points, five teammates reached double figures, and Houston beat the Los Angeles clippers 105-79 to clinch a playoff berth.
Rookie Luis Scola scored 16 points, Luther Head added 15, Tracy McGrady had 13 points, eight rebounds and nine assists, Bobby Jackson had 12 points, five rebounds and four assists, and Shane Battier scored 11 for the Rockets, who shot 48.1 percent and outrebounded the Clippers 51-33.
Josh Powell had a career-high 22 points and 10 rebounds for the Clippers (23-54), who have lost 21 of their last 25 games.
(Agencies via China Daily April 8, 2008)