The Boston Celtics missed a chance to keep the pressure on the two teams above them in the NBA's Eastern Conference after losing to the Houston Rockets on Tuesday night.

The Celtics had built a seven-game winning streak as they sought to keep pace with the rampaging, 15-straight Toronto Raptors and the first-placed Milwaukee Bucks, who have won five on the bounce.

But they were swamped in Houston with James Harden scoring 42 points and Russell Westbrook 36 as the Rockets, fifth in the Western Conference, won 116-105.

The match was tight late in the final quarter but Houston broke away with a 15-2 run that made it 116-98 with two minutes left.

Gordon Hayward had 20 points for the Celtics, who missed numerous shots throughout the match and conceded two turnovers under pressure late in the match.

In Philadelphia, Australia's Ben Simmons registered 26 points, 12 rebounds and 10 assists to lead the 76ers to a 110-103 victory over the Los Angeles Clippers.

Joel Embiid also made 26 points for Philadelphia, who have the NBA's best home record at 25-2 and sit fifth in the East.

The match was tight throughout before Josh Richardson helped Philadelphia pull away by scoring 17 of his 21 points in the final quarter, with his third three-pointer putting the home side 102-93 up with 4:44 left.

Kawhi Leonard led Los Angeles' charge with 30 points and Landry Shamet scored 19 from the bench against his former team.

LaMarcus Aldridge recorded 25 points and 14 rebounds to help the San Antonio Spurs halt a five-game losing streak in an upset 114-106 win at the Oklahoma City Thunder.

Dejounte Murray also scored 25 for the visitors, while Chris Paul poured 31 for the Thunder who are placed sixth to the Spurs' 10th in the West.

The Spurs blew out to an 11-point lead at quarter time, and held their nerve late on after the Thunder had pulled back within two points at the last change.

In Tuesday's other two games, the Washington Wizards beat the visiting Chicago Bulls 126-114 and the New Orleans Pelicans strolled to a 138-117 win at home to the Portland Trail Blazers.