If not for an old Hubie Brown DVD, the Toronto Raptors could be looking at a 3-0 hole in their Eastern Conference semifinal series against the Boston Celtics.

As he was walking toward the bus following Thursday night's come-from-behind 104-103 victory over the Celtics, Raptors coach Nick Nurse glowingly talked about the origins of the final play that ended with OG Anunoby's game-winning 3-pointer.

He told The Undefeated's Marc Spears about a set of DVDs from 2008 that featured various basketball coaches talking about different plays. The one he remembered the most featured Hubie Brown. So when his team had 0.5 seconds left to steal a victory, he went to Brown's play.

The funny thing about the play, though, is it didn't unfold according to plan.

Anunoby said it was designed for Pascal Siakam. Fred VanVleet said he was the first look. Kyle Lowry -- the 6-foot guard who somehow got the pass over 7-foot-5 Tacko Fall and into Anunoby's hands in the opposite corner -- said it was for VanVleet first, then Siakam as the second option.

No matter the design, two crucial things happened.

As Boston played zone defense on the play, Anunoby went from the corner nearest to where Lowry was inbounding the ball to the opposite corner. Celtics guard Jayson Tatum called out that Anunoby was moving.

That call didn't get answered, however, as Jaylen Brown was still guarding Siakam. As Siakam came up, Marc Gasol and Brown met in the lane. Marcus Smart tried to send Brown over to the corner to cover Anunoby but it was too late.

"It was all those actions that took place that left me open," Anunoby said.

As Lowry's pass floated in the air, Brown made a break toward a wide-open Anunoby, who short-armed his release in order to get the shot off in time.

The shot went in, but instead of going into an immediate celebration, Anunoby was stoic. He walked toward the oncoming onslaught of charging teammates who embraced him with enthusiasm.

So why didn't he celebrate right away? Well, because he knew the shot was going in, of course.

"I don't shoot trying to miss," Anunoby said after the game.

The celebration continued as Anunoby, who still barely showed any emotion as he was mobbed, saved the Raptors from going down 3-0. But it was a very different mood before the play started.

With a 2-0 series deficit and their season on the line, the Raptors saw Game 3 flash before their eyes. Tied at 101, Celtics guard Kemba Walker knifed through the Raptors' defense and dropped a perfect pass to center Daniel Theis at the rim for a slam dunk with 0.5 seconds to go.

Toronto could have sulked since it had a foul to give and couldn't find a way to foul Walker before the pass. The Raptors could have packed it in right there, trailing by two. But instead, they found deliverance from the old play once drawn up by Hubie Brown, a former NBA head coach and current ESPN analyst.

Nurse told reporters after the game that it was one of two plays he had in his pocket to use.

The Raptors coach said when he got to his players in the huddle after the Celtics took the lead, they were waiting for the play.

"No one was rattled after [Theis' dunk]," Anunoby said. "Everyone stayed confident about the next play. Let's focus on running this play and getting a good shot off. We were confident in anyone that took the shot that [they] could make it. This group is resilient. Just a next-play mentality."

VanVleet said the Raptors tried to figure out how Theis got so wide open, but then they had to quickly shift into scoring mode.

"Then you look at the clock and see how much time you got and try to run a play to get a shot up," VanVleet said. "So it was a quick timeout. We had a quick discussion about what the play was gonna be, and we decided on one, and you go out and try to execute one. Kyle made a heck of a read and OG made the shot.

"As long as there's time on the clock, you've got to believe you can win. We've been in a lot of these situations before. We've seen it all, so there was really no panic. It was moreso about trying to get a good look, and we were able to do that."

On Theis' dunk, it was Siakam who stepped up in the Raptors' defense, and that allowed Walker to slip the pass down low for the wide-open dunk. That's why he, perhaps as much as anyone, was happy to see Anunoby's shot fall as time expired.

"I was disappointed with the [dunk] because for me, I was in a position where I could've taken that away," Siakam said. "I had to make a decision, a judgment call and you can't leave the basket. That was on me right there. After that, it was, man, we have an opportunity to get a shot up. Let's do what we can. ... It was amazing. That's my guy, OG. Seeing everything he's been through and just being in that moment, for him to take that shot and make it, it says a lot."

For the first time in the series, it now feels like Toronto has momentum moving forward.

After an admittedly lackluster Game 1, in which Boston beat up on the Raptors in a 112-94 win, Toronto came back and played a strong Game 2 but ended up losing by three in part thanks to Smart's five 3-pointers in the first part of the fourth quarter.

VanVleet said that Toronto's first-round sweep of the Brooklyn Nets might have had something to do with the Raptors' slow start to this series, and now it's time for them to get back on track.

"With all due respect to Brooklyn, I don't think that got us ready to play at the level we needed to be ready for Game 1," VanVleet said. "I think the transgressions of those few days when, whether we were gonna sit or play, coupled in with laying that egg in Game 1. It was a lot.

"Then we played our butts off in Game 2 and didn't come out with a win. We expect a lot of ourselves, so to be down 0-2, I mean we knew it wasn't over, but nobody was happy. People were pissed off, the mood wasn't great. All we needed was one to get the juice back, a little magic. You know, get the momentum going on your side. We've got to try and tie this thing up Saturday."