NBA playoff betting: Expect Game 5 to come down to the wire in Boston

After the Miami Heat took Game 1 in Boston, the point spread went from -8 to -9.5 in favor of the Celtics for Game 2. After another Boston loss, the line then shifted just five points despite the Heat having home court for Game 3.

After a third loss in blowout fashion, the market sold the Celtics on the assumption that they'd given up and would no-show Game 4. So, a point spread that probably should've been around Celtics -2 in Miami was -4.5 before the Heat were favored in the following game.

Now that the Celtics have extended the series back to Boston, our hypothesis about those dual overreactions in Miami was confirmed as Thursday night's Game 5 has an associated point spread right back to where it was in Game 1.

Heat @ Celtics (-8.5, 215.5)

The Celtics have largely struggled at home after two big blowout covers in their first two playoff games, losing five contests outright. Although they covered big numbers in the two times they've won - Games 2 and 7 against Philadelphia - there's more reason to believe in the playoff resumes of Erik Spoelstra and Jimmy Butler than those of Doc Rivers and James Harden.

Add in the Heat's 5-3 road playoff record, including one loss without Butler, and you could make the case there's too much home-court advantage built into this number. Of course, as we've been following throughout the playoffs, there's also the simple element of rating. If we're looking at point spreads based on pre-series ratings, the Heat are likely again being underrated in the market. Meanwhile, the Celtics' rating hasn't seemed to change despite having a 9-8 playoff record.

While much has been made of Boston's odds to complete a historic comeback dropping down to a palatable +240, let's trust the Heat's staff to counter the Celtics' adjustments from Game 4. More importantly, Miami should also bring a more concerted effort knowing that Boston will be fully engaged for 48 minutes. So, even if you're holding Heat tickets to win the series, we'll back Miami to at least keep this game close, even if Boston extends its playoff life for another day.

Pick: Heat +8.5

Grant Williams over 7.5 points (-115)

After a stretch where Grant Williams played little-to-no minutes against the Sixers and Heat, the Celtics have turned to him for a significant role.

While history may remember Williams' conference finals role for his ill-fated attempt to get in Butler's head, he's played more than 25 minutes in each of the last three games. The Heat seem willing to give Williams a chance to beat them, surrendering at least six field-goal attempts and nine points to him when he's played in a game. We'll back him to score more than 7.5 points Thursday.

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.