Embiid starred after learning earlier in the day that he was selected as a starter in the upcoming NBA All-Star Game. Embiid was the first Philadelphia player selected to start since Allen Iverson in 2009-10.
Embiid scored 20 or more points for the 24th time this season.
Dario Saric scored 16 points and T.J. McConnell had 15 for the Sixers, who inched above .500 by one game and won without sharpshooting guard JJ Redick, out due to a leg injury. The last time the Sixers were above .500 came on Dec. 12.
Al Horford and Marcus Morris paced the Celtics with 14 points each while Marcus Smart added 13 and Jaylen Brown had 12.
Jayson Tatum contributed 11 for Boston, which played without All-Star starting guard Kyrie Irving, out because of a shoulder injury.
The Celtics had won the previous three matchups this season.
The Sixers built a 21-point advantage in the second half, but they have had trouble holding onto double-digit leads all season.
After the Celtics crept back within 82-68, Simmons responded with a nifty layup to put the Sixers back up 16 with 4:45 remaining.
Tatum drained a 3-pointer from the baseline to close the Celtics within 86-79 with 2:01 left. After a turnover, Horford missed a trey to potentially cut the lead to four. Horford and Brown each missed a 3-pointer on the Celtics' next possession.
The Sixers surged to a 71-53 advantage after the third as McConnell provided a major spark with nine points in the final 2:29.
Boston was hampered by a slew of turnovers, with 18 through the third. The team committed 15 alone in the first half, more than its season average of 14.1.
The Celtics also struggled with their shooting, going 4 of 22 from beyond the arc through the third.
It was only the fourth time in franchise history that the Sixers held the Celtics to 53 or fewer points through three quarters.
--Field Level Media
Philadelphia | Boston | |
Joel Embiid 26 | Scoring | Al Horford 14 |
Joel Embiid 6 | Assists | Jaylen Brown 4 |
Joel Embiid 16 | Rebounds | Marcus Morris 6 |
Joel Embiid 6 | Free Throws Made | Marcus Morris 4 |
T.J. McConnell 3 | Steals | Shane Larkin 2 |
Joel Embiid 2 | Blocks | Al Horford 2 |
Team | Points | FG% | 3PM-3PA | FTM-FTA | Assists | Rebounds | Blocks | Steals | Turnovers |
Philadelphia | 89 | 46.6 | 6-17 | 15-17 | 18 | 41 | 5 | 10 | 25 |
Boston | 80 | 40.5 | 7-29 | 13-17 | 13 | 31 | 5 | 7 | 19 |