PHILADELPHIA -- Donyell Marshall was so surprised his name was called to enter the game that he didn't even hear it.
"Coach had to say it again," Marshall said.
Andre Iguodala led the 76ers with 21 points, Thaddeus Young had 17 and Samuel Dalembert grabbed 12 rebounds for Philadelphia, which won its third straight and moved within two games of Miami for fifth place in the Eastern Conference.
Dwyane Wade, coming off a 50-point performance in a triple-overtime victory over Utah on Saturday, was held to 18. The NBA's leading scorer looked tired after playing a career-high 52½ minutes against the Jazz. He shot 8-for-21 in 34½ minutes.
"I didn't have the energy," said Wade, who averaged 43.3 points in Miami's three wins last week.
Jermaine O'Neal led the Heat with 20. Miami fell 2½ games behind Atlanta for fourth place in the East. The top four teams get home-court advantage in the first round of the playoffs.
With Wade sitting on the bench to start the fourth quarter, the 76ers made their run. Marshall's 3-pointer tied it at 70 and Andre Miller's jumper put Philadelphia ahead 72-70, capping an 11-2 run.
After Wade made a pair of free throws, Louis Williams scored on a driving layup and Marshall hit another 3 to make it 77-72. Marshall hit one more from beyond the arc for an 80-74 lead and the Heat never recovered.
Marshall hadn't scored a point since Feb. 17 and the 14-year veteran has played in only 14 games this season. But he rescued the 76ers when they desperately needed someone to step up.
"We got a great spark from Donyell," 76ers coach Tony DiLeo said. "He was well-rested. He's a professional. He works out every day and he came in and performed. Their zone [defense] slowed us down. We knew we'd put him in at some point. We know he can make a shot."
But when DiLeo made the call to end of the bench, Marshall wasn't listening because he hardly ever plays.
"It shows when your team needs a game, Coach is willing to do whatever we need to get a win," Marshall said. "It doesn't mean I'm going to play the next game."
Perhaps a little weary after a spectacular effort a day earlier, Wade rested nine minutes in the first half. By the time he returned midway through the second quarter, the Heat had cut an eight-point deficit to 35-32.
Wade had fresher legs early in the third quarter. He hit an 18-footer to start it off and added a driving layup in the opening minutes. His steal and layup put the Heat ahead 51-50 during a 9-0 run. Wade also came out of nowhere to block Willie Green's shot on defense. But he also shot airballs on two shots in the quarter, showing signs of fatigue.
Despite playing their longest game in 17 years, the Heat weren't sluggish at the start and were strong until the fourth quarter, when they scored just nine points. Miami finished 2-for-17 from field in the final 10 minutes.
"We were probably fatigued," Heat coach Erik Spoelstra said. "There are games where you can't close them out."
The 76ers, who had a day off after closing out the Spectrum on Friday night, looked like the tired team most of the game. They shot just 38.7 percent (6-for-23) in the third quarter, turning a three-point lead into a 68-61 deficit.
The teams went back-and-forth in the first half and the 76ers took a 46-43 lead after two quarters. Miller made a perfect bounce pass through traffic to Iguodala, who completed the fast break with a two-handed dunk to make it 45-43. Miller's free throw on the next possession made it 46-43.
"That was an important game for us," DiLeo said. "We hung in there and kept playing hard and thought at some point, maybe from their fatigue, they would wear down a bit."
Wade had scored 40 or more in six of his previous 11 games and had at least 30 in nine of those games ... The 76ers have won six straight over Miami at home and 16 of 18. ... Philadelphia plays five games in a seven-day span on the road against Western Conference opponents, starting with the Los Angeles Lakers on Tuesday night. .. The Heat fell to 12-19 on the road. ... The 77 points allowed was a season-low for Philadelphia.