Cleveland's skid comes on the heels of a 13-game win streak.
Howard was 8-for-13 shooting and added four blocks, and Vince Carter had eight of his 11 points in the fourth quarter to help the Magic beat Cleveland for the first time this season.
O'Neal made his first eight shots and finished with 20 points, and LeBron James had 33 points and nine rebounds for the Cavaliers, who were eliminated by Orlando in last year's Eastern Conference finals.
After starting his Cleveland career 0 for 12 from the field, Antawn Jamison made his first shot of the game, a layup with 7:29 remaining in the first quarter. He finished with 19 points.
In Denver, J.R. Smithscored 16 of his 19 points in the fourth quarter and Denver recovered to get the win after blowing an early 20-point lead.
Chauncey Billups had 26 points and Carmelo Anthony added 23 for the Nuggets, who avoided back-to-back losses for the first time since late December with the victory over the NBA's top road team.
Ray Allen had 25 points and Kevin Garnett, Rajon Rondo and Marquis Daniels added 15 points apiece for the Celtics, who lost for the first time in their last four road games. They remain an NBA-best 20-10 away from home.
In Minneapolis, Kevin Durant scored 32 points to extend his streak of games with at least 25 points to 28 games and Russell Westbrook had a triple-double to lead Oklahoma City to its ninth straight win.
Westbrook had 22 points, 10 rebounds and 14 assists and Jeff Green added 17 points and 14 rebounds for the Thunder, who have the longest active winning streak in the NBA.
Jonny Flynnand Kevin Love each had 19 points for the Timberwolves, who have dropped five in a row.
Durant scoring streak surpasses Allen Iverson's 27-gamer in 2001. It's the longest since Michael Jordan had 40 straight games of 25 or more points in the 1986-87 season.
Carlos Boozer scored on an offensive put back at the end of regulation to force overtime, then gave Utah its first lead since the opening minutes, and Utah rallied from down 25 in the third quarter to stun Portland.
Boozer had 22 points and a career-high 23 rebounds for the Jazz, who trailed 64-39 with 7 minutes left in the third quarter. They outscored the Blazers 44-19 over the final 19 minutes to send it to overtime.
Brandon Roy led Portland with 23 points and Marcus Camby had 18 rebounds.
Deron Williams added 18 points and 12 assists for the Jazz.
In Auburn Hills, Mich., Richard Hamilton scored 27 points and Rodney Stuckey added 20 and Detroit held on for the win after trailing to start overtime.
Manu Ginobili's layup tied the game at 93 with 27.5 seconds left, and the Pistons missed two game-winning shots at the end of regulation.
Detroit was down one at the OT tip because of a technical foul on Hamilton, but ripped off an 8-2 run to start the extra period.
Tim Duncan had 29 points and 10 rebounds for the Spurs.
In East Rutherford, N.J., Rudy Gay scored 29 points and Memphis added another exclamation point to a frustrating season for New Jersey, rallying from an 18-point first-half deficit for the win.
O.J. Mayo scored 10 of his 24 points in a 17-point run that bridged the third and fourth quarters and put the Grizzlies ahead for good, adding to the woes of the Nets (5-51).
Zach Randolph added 18 points and 10 rebounds and Marc Gasol tallied 14 of his 16 points in the second half for Memphis, which won for only the third time in 11 games.
Brook Lopez had 26 points to lead the Nets, who led 36-20 after their highest-scoring first quarter of the season.
In Oakland, Calif., Stephen Curry scored 32 points and made the go-ahead free throw in the final minute after a technical foul on Jamal Crawfordto help Golden State edge Atlanta.
Monta Ellis scored 26 for the Warriors, who got their first win against a team with a winning record since beating Boston on Dec. 28.
Joe Johnsonled Atlanta with 31 points, Al Horford added 26 and Josh Smith had 14 points and 17 rebounds. The Hawks have lost three of four.
In Phoenix, Jason Richardson scored 26 points, Amare Stoudemire had 19 points and 14 rebounds, and Steve Nash had 17 assists as Phoenix completed a season series sweep of Sacramento.
Newly acquired Carl Landry led Sacramento with 18 points. Beno Udrih had 17 and Donte Greeneand rookie Tyreke Evans each scored 16 for the Kings.
The Kings began the season 9-8, but since then they are 9-30. They are 5-25 on the road and have lost nine straight in Phoenix.
In New Orleans, David West scored 27 points, including four in the final 2 minutes, to lift New Orleans to the win.
Darren Collison added 26 points for New Orleans, the fifth straight game he's had 24 or more.
Chase Budinger scored 18 points and Aaron Brooks added 15 for Houston, which has dropped two straight.
