LOS ANGELES (AP) -- Dwight Howard missed a two-handed dunk on his first shot, and the night never got much better for the Los Angeles Lakers.
When Howard and Steve Nash took their places alongside Kobe Bryant and Pau Gasol under the Hollywood spotlight, the Lakers opened a season of enormous expectations with an equally big dud of a performance.
Darren Collison scored 17 points, Brandan Wright added 14, and the Dallas Mavericks spoiled the Lakers debuts of Howard and Steve Nash with a 99-91 victory over Los Angeles on Tuesday night.
In his first regular-season game in a gold jersey, Howard had 19 points and 10 rebounds while missing 11 of his 14 free throws before fouling out with 2:02 to play.
That's hardly the debut he anticipated after arriving in a trade with Orlando last August, but not much has gone according to plan in the first month for the Lakers' starters, who barely played together in their winless preseason due to injuries.
''It's not an excuse, but it will all come with time,'' Howard said. ''We haven't had an opportunity to really play together as much as we want, but we're going to get it. ... We're going to chip away, and we're going to get better.''
The Lakers' superstar newcomers both had debuts to forget. Nash managed just seven points and four assists while trying to balance the Lakers' new motion offense with his own strengths on the pick-and-roll - all while getting roundly outplayed by Mavs newcomer Collison.
''It's growing pains, and it's a struggle,'' Nash said. ''We're out of sync, and we're going to probably have some more moments in games like that.''
O.J. Mayo had 12 points as the Mavericks pulled off a stunner in their opener, comfortably beating the Lakers without any help from injured Dirk Nowitzki. Dallas and Los Angeles both made big moves in the offseason, yet the Mavericks appeared to be much more together than their high-profile rivals.
''It's a great win,'' Dallas coach Rick Carlisle said. ''If you execute in this league and have talent, you have a chance to win, and we did that. The Lakers are going to be fine. They've got a lot of new guys and a new system, but we were opportunistic tonight and got the job done.''
Bryant scored 22 points while playing on an injured right foot for the Lakers, whose loaded lineup followed up its 0-8 preseason with a largely passionless second-half effort in front of a sellout crowd expecting to see a super team capable of contending for the franchise's 17th championship - a fact acknowledged by Bryant when he addressed the fans before the game.
''As you know, we have a lot of expectations this season,'' Bryant said. ''We're trying to live up to the expectations. We're trying to bring another championship back to where it belongs, back to Los Angeles.''
Instead, the Lakers showed how much work they will have to do to challenge Miami and the NBA's best.
Dallas steadily pulled away to a 16-point lead in the second half, never allowing any serious runs by their disjointed, disorganized opponents as the Lakers lost their opener for just the fourth time in the last 21 years.
''It's not the way we wanted it to go,'' said Gasol, who led the Lakers with 23 points and 13 rebounds. ''We know it's not going to happen for us right away, but we've just got to stick with it.''
Vince Carter, Shawn Marion and Rodrigue Beaubois scored 11 points apiece for the Mavericks, who snapped a six-game skid against the Lakers over the past two seasons.
Dallas also contained Howard by using his career-long free-throw ineptitude against him - hardly a novel strategy, but one that worked particularly well when combined with Howard's opening-night nerves.
''When he had me in a bad position, I wanted to foul him,'' said Elton Brand, who had eight points and 11 rebounds in his Dallas debut. ''Underneath the basket, he's a beast and he's hard to stop. I know he can dunk, and I know he can make those tough layups, so I'm playing the percentages. He obviously hasn't been a good free throw shooter, and tonight he was 3 for 14.''
The Lakers were 12 for 31 altogether from the free-throw line, a major factor in their inability to close the gap on Dallas in the second half.
''I've just got to stop thinking so much and get up there and make them,'' Howard said.
Jae Crowder scored eight points in his NBA debut for the Mavericks, who are likely to be without Nowitzki for at least six more weeks while the German superstar recovers from arthroscopic knee surgery. Dallas also played without new center Chris Kaman, yet had little trouble containing the Lakers down low.
NOTES: Dallas opened its season on the road for the first time since 2007. The Mavericks had opened the season against the Lakers three previous times, losing all three games. ... Howard was called for a flagrant foul in the third quarter for hammering Brand on an open shot in the lane. ... Katy Perry, Russell Brand, Floyd Mayweather Jr., Adam Levine, Jon Cryer and Los Angeles Galaxy stars David Beckham and Robbie Keane attended the game.