LAKE BUENA VISTA, Fla. — The Toronto Raptors were a half-second away from falling into the abyss that no NBA team has ever escaped. Down by two points, down by two games, the reigning champions needed a miracle.

OG Anunoby delivered.

Anunoby caught a cross-court pass that Kyle Lowry threaded over everybody else on the floor and hit a 3-pointer as time expired, giving the Raptors a 104-103 win over the Boston Celtics in Game 3 of their Eastern Conference semifinal series Thursday night.

The Celtics still lead the series 2-1. But it’s not 3-0 – and that means the Raptors still have realistic hope. The Raptors mobbed Anunoby after the shot, reveling in the moment.

“Someone hit me in the nose,” Anunoby said. “It’s cool.”

The Celtics took a two-point lead when Kemba Walker found Daniel Theis for a dunk with a half-second left.

No team in NBA history has rallied from a 3-0 series deficit. The Raptors won’t have to try it now; Lowry elected to audible and throw the long pass – threading it over Boston’s 7-foot-5 Tacko Fall, who was put in specifically to disrupt the inbounds play – to Anunoby.

“The pass was nothing,” Lowry said. “OG made the shot. All the credit goes to the shot, man. That’s a tough shot. Give OG that credit. The pass was just to get it to a guy like OG. It’s OG’s moment, man. That’s a great moment for that kid.”

Lowry played virtually the whole way, finishing with 31 points, eight assists and six rebounds. Fred VanVleet scored 25 points, Pascal Siakam had 16 points and Anunoby 12.

Walker scored 29 points for Boston, which lost for the first time in seven playoff games. Jaylen Brown had 19 points and 12 rebounds and Jayson Tatum finished with 15 points, nine rebounds and six assists for the Celtics.

“It hurts and stings to lose,” Celtics Coach Brad Stevens said. “But we’ll just get back to it and get ready for Saturday.”

Marc Gasol made a layup with 5:57 left for a four-point lead; the Celtics responded with the next eight points, going up 99-95 on a dunk by Brown with 3:02 remaining.

Lowry got a pair of layups, both drawing Toronto within two. The Raptors had the ball with a chance to tie or take the lead in the final half-minute, and VanVleet made an acrobatic layup with 21.5 seconds left, knotting it at 101.

Theis’ dunk put Toronto on the brink. Anunoby rescued the champs.

“Much credit to those guys,” Walker said. “That was a hell of a shot.”

Toronto was clawing uphill most of the night. The Raptors were outscored 19-10 to close the first half, a run that gave Boston a 57-47 lead at the break. Walker had 17 points in the first quarter, capping it with a 3-pointer – and did it again to end the second and give Boston its biggest lead.

“We knew they wouldn’t quit,” Walker said.

Lowry had been 0 for 5 from 3-point range – and 1 for 17 in the series – before connecting from the left corner midway through the third, getting the Raptors to within 61-60. Toronto eventually led by as many as four later in the quarter, but Boston reclaimed the lead and took an 80-76 edge into the fourth.

In the final moment, the Raptors found a way.