That includes Monday night's game in which Dwyane Wade scored 30 points as the Heat earned a 94-87 win at AmericanAirlines Arena, tying the series at two games apiece.
"This is one heck of a series," Heat coach Erik Spoelstra said. "Was there any doubt this was going to overtime?"
Game 5 in the best-of-seven battle of attrition is Wednesday at Toronto.
The Heat have been without forward Chris Bosh (blood clots) since the All-Star break, and center Hassan Whiteside is likely out for the rest of the series due to a knee injury he sustained Saturday.
For Toronto, center Jonas Valanciunas, also hurt Saturday, is out for the series due to a sprained ankle, shooting guard DeMar DeRozan is playing with a jammed right thumb, and point guard Kyle Lowry fouled out Monday with 1:58 left in regulation.
The Heat, though, has the 34-year-old Wade, who is averaging 27.3 points in the series, playing as if he has turned back his odometer.
There is a reason for that, Wade said.
"I put in a lot of hard work behind the scenes," Wade said. "I worked my tail off this summer to get to where I can still play at an elite level.
"When I'm healthy, I can play as good as anyone. After all the work I put in, somebody has to pay for it -- that's my mentality."
On Monday, that was the Raptors, who blew a seven-point, fourth-quarter lead.
The Raptors had a chance to win the game in regulation, but Cory Joseph missed a 17-foot jumper at the buzzer.
Toronto coach Dwane Casey said the plan was not for Joseph to run isolation.
"We ran a play, but (Miami) took something away," Casey said. "We have to give them credit for taking the play out, but I thought Cory still had a good look even after the play broke down."
In the previous possession, Wade drove to the basket and tied the score 83-83 with 12.6 seconds left.
Joseph, who finished with 14 points off the bench, was playing because Lowry fouled out.
"I'm (mad)," Lowry said of the loss. "I can't be in foul trouble. I let my team down."
Miami got the first basket in overtime -- an acrobatic tip-in by rookie Justise Winslow with 3:36 left -- and never trailed again.
Winslow finished with nine points on 4-of-5 shooting in 31 energetic minutes. That came after he was not used at all in Game 3.
"I'm sure he was angry," said Spoelstra, who decided to leave his first-round pick on the bench Saturday.
After Winslow's play, Heat forward Joe Johnson, who had two blocks in overtime, made a jumper. Goran Dragic had a three-point play to put Miami up 92-87, and Wade's steal and dunk put an emphatic stamp on the Heat's win.
Neither team shot well. Miami shot 45 percent from the floor, and Toronto shot 39.3 percent.
In fact, the offensive futility was symbolized by a Wade shot in overtime than got stuck on the rim, resulting in a jump ball.
"I expect that to happen on the road, not at home," Wade said. "I was expecting a friendly bounce."
Toronto got 13 points and 13 rebounds from Bismack Biyombo, who replaced Valanciunas.
Lowry was held to 10 points on 2-for-11 shooting, though he added nine assists. DeRozan had nine points on 4-of-17 shooting. Joseph and Terrence Ross paced the Raptors with 14 points apiece.
Raptors coach Dwane Casey said he held DeRozan out of the second half for as long as he could.
"But we ran out of bodies when Lowry went out," Casey said. "(DeRozan's injury) is a concern. He's been getting treatment. He's a tough kid. He's trying to play through (the ailment)."
DeRozan said he is trying to stay positive, but ...
"The feeling is uncomfortable, not doing things I normally do with gripping the ball," he said. "My missed layup showed me how much I have to deal with it.
"But I know I'm not going to shoot like I did tonight in the next game. I know that for a fact."
NOTES: Heat C Amar'e Stoudemire, who had six points and three rebounds, started in place of C Hassan Whiteside. ... In Game 3, Heat coach Erik Spoelstra sat starting 6-foot-3 PG Goran Dragic for the final six minutes, opting for a longer defender in 6-6 rookie G Josh Richardson. On Monday, Spoelstra played Dragic for all 12 minutes of the fourth quarter and all five minutes of overtime. Dragic finished with 15 points in 43 minutes. ... Heat SG Dwyane Wade was harshly criticized on social media because he was doing his pregame shooting ritual while the first part of the Canadian national anthem was being sung prior to Game 3. After Monday's game, Wade said: "I apologize for Canada thinking I would disrespect them as a country. I have respect for the country of Canada."