(SportsNetwork.com) - The Miami Heat embark on a four-game road trip, starting Sunday afternoon against the Boston Celtics at TD Garden.

This was once one of the best rivalries in the NBA, but times change.

For the Celtics, Doc Rivers was traded to coach the Los Angeles Clippers, Kevin Garnett and Paul Pierce were shipped to the Brooklyn Nets and Ray Allen is apparently still deciding whether or not to play this season.

For the Heat, the four-time reigning Eastern Conference champions, a fellow named LeBron James bolted South Beach for his hometown Cleveland Cavaliers. And, for the time being, Dwyane Wade is sidelined with a right hamstring injury.

Both teams are under .500 and both teams are in the midst of two-game losing streaks.

The Heat begin this trek Super Bowl Sunday and will stop in Detroit, Minnesota and San Antonio.

They dropped both games on a short homestand, first to the Milwaukee Bucks, then to the Dallas Mavericks.

On Friday, the Heat turned a double-digit lead into a 93-72 loss to Dallas.

The Mavericks held the Heat to just three points over a nearly 14-minute span in the third and fourth quarters. Dallas went on a 39-3 run during that time to end a seven-game, regular-season losing streak to the Heat.

Miami's stale finish -- which came after Dallas started the game ice-cold from the field -- tempered what was a career night for Hassan Whiteside, who set a franchise record with 14 rebounds in the first quarter.

The 7-foot center ended with 16 points and a career-high 24 rebounds for the Heat.

James Ennis added 15 points off the bench, All-Star Chris Bosh scored 12 and Mario Chalmers had 10 in Miami's fourth loss in six games.

"We anticipated that this probably wouldn't be a game where we'd win by outscoring them, we'd have to keep this game down," said Heat coach Erik Spoelstra. "Second half, they dominated and played their style."

The Celtics came back from a 3-3 road trip with a home loss to the Houston Rockets, 93-87, on Friday. Boston dropped the last game on the sojourn to the Minnesota Timberwolves for its two-game slide.

Against the Rockets, Brandon Bass and Marcus Thornton each scored 17 points for the Celtics. Tayshaun Prince chipped in 13 off the bench and Avery Bradley managed 10.

Boston has lost three of its last four.

Bass capped a 9-2 run with a pair of free throws to help the Celtics, who were down as many as 19 earlier in the game, close to within three just past the midway point of the fourth.

Donatas Motiejunas did damage for the Rockets, converting crucial buckets to keep the Rockets ahead. The Celtics had numerous opportunities to get closer in the final minutes, however, Josh Smith's free throws put the Rockets up seven with 51.6 seconds to play.

Thornton's layup preceded an offensive foul by James Harden that trimmed the Boston deficit to 90-87 with 27 seconds left. Corey Brewer converted a pair of free throws before Bradley's missed 3-pointer sealed it for the visitors.

"I thought we played with much more urgency," said Celtics coach Brad Stevens of the second half.

The Heat won the first game between the two teams this season back in December and have won five of the last eight regular-season matchups. Boston is 11-1 in its last 12 regular-season games versus the Heat as the host.