TORONTO -- Miami Heat coach Erik Spoelstra was impressed with his club's mental toughness Tuesday night.

After Toronto guard Kyle Lowry forced overtime by hitting a half-court, buzzer-beating 3-pointer, Miami opened the extra period on a 8-0 run and hung on for a 102-96 victory over the Raptors on Tuesday night.

The Heat took a 1-0 lead in the best-of-seven Eastern Conference semifinal series. Game 2 is Thursday night in Toronto.

"Kyle Lowry's three, as soon as it left his hands, I think everyone in the building kind of had an idea that would go," Spoelstra said. "From that point on, I was extremely proud of the group.

"To get knocked down on the canvas like that, the air punctured out of your body, to show the mental resolve to come back and take control of overtime -- that's great mental toughness that I think we showed from there."

Goran Dragic had a game-high 26 points for Miami, and Dwyane Wade added 24 points, six rebounds and four assists. Joe Johnson chipped in with 16 points and seven rebounds.

The Heat started the fourth on a 7-2 run to build a 10-point lead. Toronto responded with a 12-4 surge late to pull to within 83-81. Dragic appeared to kill the Raptors' momentum by sinking a 3-pointer with 40.6 seconds remaining, and Miami led by six after Josh Richardson sank two free throws with 19 seconds left.

"Obviously, in the fourth quarter with them coming back, we did a lot of things wrong that we need to correct going into the next game," said Wade, who had seven points in overtime.

Jonas Valanciunas led Toronto with 24 points and 14 rebounds. DeMar DeRozan chipped in with 22 points, six rebounds and four assists, while Terrence Ross added 19 points off the bench.

The loss drops to Toronto 1-9 in playoff series openers.

Lowry struggled all night, going 0-for-5 from 3-point range prior to the game-tying shot. He finished 3-for-13 from the field for seven points in the loss. Despite the struggles, the Raptors believe he will break out of the slump, which had him averaging 13.9 points per game in the opening-round series against the Indiana Pacers.

"Even though he didn't shoot the ball well, he was effective down the stretch," Raptors coach Dwane Casey said. "He got stuff done. I thought his bulldog tenacity set the tone for us defensively. We know he's not shooting the ball well, he's not making plays with shots that he normally makes.

"Just like a hitter (in baseball), hitters go through slumps. He's there, but we have to believe in him, we do believe in him, and he's going to come out of it."

Added DeRozan: "I tell him all the time, good or bad, I have the utmost confidence in him. I don't care if you miss 15 shots, I'm going to stand behind him just like if he's making 15 shots in a row. He'll come around."

Miami shot 57.9 percent in the third quarter to erase a two-point halftime deficit and take a 68-63 lead into the fourth.

Dragic had 10 third-quarter points, helping the Heat build a five-point lead. Wade added nine third-period points, moving into 16th place on the NBA's all-time postseason scoring list.

Ross, who averaged just five points per game through the first seven games of the playoffs, led the way with 11 second-quarter points off the bench, helping the Raptors to a 43-41 lead at the break.

Valanciunas scored 10 points and DeRozan added eight as the Raptors and Heat were tied 18-18 after one quarter.

The Heat received a scare 7:06 into the first when Hassan Whiteside slipped on the floor and strained his right knee. Whiteside labored on the court but was able to limp off the floor during a timeout.

He went to the Miami room for further observation and returned for the second quarter.

NOTES: Raptors G Norman Powell started in place of F Patrick Patterson. ... Heat F Chris Bosh, who has been in a dispute with the club over his health status, made the trip to Toronto, where he spent the first seven seasons of his career, but was inactive for Game 1. Bosh has been sidelined since the All-Star break because a blood clot was found in his left leg. ... Miami F Dorell Wright and Raptors G Delon Wright became the first brothers to face one another in a playoff series since G Jrue Holiday (New Orleans Pelicans) and G Justin Holiday (Golden State Warriors) met in April 2015. ... Toronto won the regular season series with Miami 3-1.