NBA playoff betting: Now or never for the Heat to avoid historic collapse?

Now it's time to get nervous.

A team has never blown a 3-0 lead in an NBA playoff series. Of the 150 times a club has faced that deficit, no team entered its series as much of a betting favorite as the Celtics did. Referencing that stat is largely meaningless in betting context given the short odds sportsbooks have offered for the comeback.

With the admission of Boston's decent chance to pull it off, we should be reminded that it's not like all 150 of those 3-0 series were won in sweeps or in Game 5. Sure, most did. But the series leader needed a Game 7 to close out their opponent in three instances.

If the Heat win Saturday, this matchup goes the way of the 2003 Blazers-Mavericks series or 1994 Nuggets-Jazz - largely forgotten. However, if Miami doesn't win Game 6 at home, it faces a Game 7 on the road, where it'll be nearly a double-digit underdog. The previous three teams to give up a 3-0 lead weren't in that position.

Throw out the record books for what is truly a unique situation. Those of us who backed the Heat at the start of the series - at a big underdog price at +400 or better - can take solace in knowing we made a good bet. At no point was there a better price on Miami, even if it chokes away a ticket to the NBA Finals.

Celtics @ Heat (+2.5, 211)

Sanity has prevailed when it comes to the point spread for Game 6. You may recall that we documented how the previous two contests played in Miami were wild overreactions to the value of each side. We hypothesized that the proper point spread for a Celtics-Heat game in Miami should be about -2. Game 3 closed Boston -4.5, and Game 4 closed Miami -1.5. Understanding what the line should be and then blindly fading the move away from that number would have provided two winning bets. More importantly, it's a lesson worth taking into other games and sports.

But none of that helps us here, as this line gives the Celtics a modest boost on the idea that they have some momentum or that the Heat will be without Gabe Vincent again. In this case, momentum has come from one element of the game that has shifted more than any other: 3-point shooting.

Through the opening three contests in the series, the Heat shot 48.2% from the 3-point line compared to the Celtics' 29.2%. Boston's adjustment was to fire away and beat Miami's defense by shooting over it. It succeeded by making 40% of 84 total threes in Games 4 and 5, while the Heat's shooting chilled out at 30.9%.

In this modern era of the NBA, we're not reinventing any sort of wheel by saying that whoever shoots it better will likely win the game. However, between the Celtics' willingness to settle for outside shots - an unusual trait for a favorite without a historically great shooter - and the Heat's need to make up for a talent discrepancy via the 3-pointer, that's likely the case.

The Heat and Celtics have shot at a nearly identical clip of 38% through the playoffs, and Boston has kept that rate up on the road. However, coaching is one advantage Miami's had throughout the series. If you're relying on that edge, now would be a good time for Erik Spoelstra and his staff to make an adjustment limiting the quality of deep looks for Boston.

Getting Vincent back would be important for the Heat to provide on-ball defensive pressure on Jaylen Brown, who had his best effort in Game 5. One positive for Miami is that it got 36 positive minutes from Haywood Highsmith - an athletic role player who could step up at home. He appears to be a better matchup option than Kevin Love.

If the Celtics hit seven threes in the first quarter again to take a 15-point lead and hold it the rest of the game, then you tip your cap. If Derrick White can shoot the lights out on the road - as he did at home - you acknowledge it's not your day.

The Heat aren't stupid - they know this is their best chance to avoid humiliation. I'll expect more from the supporting cast at home and a return of peak Jimmy Butler, while the Celtics' role players don't come out as hot in the first half as they did in an energetic home environment.

Pick: Heat moneyline (+120)

Matt Russell is the lead betting analyst for theScore. If there's a bad beat to be had, Matt will find it. Find him on Twitter @mrussauthentic.