The Boston Celtics and Miami Heat have locked horns in what has been a physical, bruising NBA Playoff matchup. While the series has been close, the margin of victory in each contest has been anything but, as four of the five games have been decided by double digits.

The Celtics seem to have broken through, however, as they have won each of the last two contests to take a three-games-to-two series lead. Boston secured a 93-80 win in a knockdown, drag-out defensive battle against the Heat that featured lackluster shooting from both teams in the first half.

Powered by another strong performance from star guard Jaylen Brown, the Celtics raced past the Heat in the second half to put themselves one win away from their first NBA Finals appearance since the 2009-10 season. Boston held the Heat to under 90 points for the second straight contest, as they remained focused on the defensive end in the second half.

Faced with their own NBA Playoff elimination, the Heat must now pick up the pieces and find a way to send the series to a Game 7 back in Miami. But with the curious disappearances of star center Bam Adebayo and guard Kyle Lowry, and the injury to forward Jimmy Butler, Miami certainly has an uphill battle.

The Heat are as tough as they come and can't be counted out. Still, it's hard to look at this Celtics team that has advanced to the Eastern Conference Finals in three of the last six seasons and not think that this is their time.

As the series shifts back to Boston for Game 6 on Friday night, the Celtics can prove that their time has arrived with an NBA Finals-berth clinching win.

Here are three reasons why Boston will beat the Heat in Game 6.

3 Reasons Celtics Will Beat Heat To Advance To NBA Finals 

3. The Heat look defeated 

The Heat are saying all the right things in their postgame pressers, emphasizing the need to do better. However, time is dwindling for them to do so.

A playoff veteran, Lowry has battled a hamstring injury and has shot a combined 1-for-12 from the field in the series' last two games. Butler, who sustained a knee injury in Game 3, hasn't looked like the player who was taking the NBA Playoffs by storm in the first two rounds. Adebayo was curiously nowhere to be found in the second half after a strong first two quarters of play in Game 5.

After Game 5, Heat head coach Erik Spoelstra, undoubtedly in an attempt to inject some life into his team, said that “you've got to enjoy this”, with this being the chance to fight back and punch a ticket to the NBA Finals.

Unfortunately for Speolstra, it looks like the Heat aren't enjoying anything right now. They look defeated.

2. The Celtics' defense is continuing to do what they've done all postseason long

The Celtics' defense has allowed the second-fewest points per game in the NBA Playoffs, second only to the Heat. However, their unit has been on another level in the last two games, allowing an average of 81 points on just 32.6 percent shooting from the field.

They permitted just seven three-pointers on a whopping 45 attempts to a Heat team filled with some of the better three-point snipers in the league.

Boston has clamped down on the paint as well, permitting just 68 points in the painted area to a Heat team that ranked among the league's best at attacking the basket during the regular season.

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Celtics head coach Ime Udoka spoke about how the team believes their defense has “put mental stress and strain on teams.” We're watching that unfold in front of our very eyes, as there is no easy solution available to the Heat for cracking the code against this Boston defense.

1. Jaylen Brown has been on another level

Make no mistake. Brown has been great in these NBA Playoffs. However, in Games 3 and 5, excluding his lackluster Game 4 showing, he has been on another level.

40 points on 70 percent shooting in Game 3. 25 points on 52.6 percent shooting in Game 5. Even more impressive is the fact that he rebounded from a 2-for-7 shooting performance in the first half to finish with such a line on Wednesday night.

Brown flushed his bad performance, just as the Celtics have flushed away their losses this postseason. The exclamation point to his second half explosion was a resounding, look-out-below dunk over Bam Adebayo, one that left even Heat president Pat Riley looking defeated.

With Brown playing at this level, the Celtics will be even more difficult to beat.