Lowe: The biggest questions that could decide Boston Celtics-Miami Heat Game 5

If there's one thing to glean from four games filled with injuries and wild runs, it's this: These might be the two best defenses in basketball -- and the Eastern Conference finals will be won in the muck. Issac Baldizon/NBAE via Getty Images

This topsy-turvy, injury-riddled series between the Boston Celtics and Miami Heat has been so strange that the magnitude of tonight's Game 5 in Miami almost sneaks up on you.

Marcus Smart, Kyle Lowry, Al Horford, Jimmy Butler, Tyler Herro, Jayson Tatum and Robert Williams III have missed some or all of at least one game. That has robbed this series of any rhythm. Each game has been its own entity. It almost feels as if the real series hasn't started, yet one team tonight will give itself two chances to win one game and advance to the NBA Finals.

Every chance at this late stage is precious. Miami has already nailed one of the greatest instant rebuilds in modern sports history, chasing its second Finals in three years despite having almost zero cap flexibility or tradable assets only a half-decade ago. Its two most accomplished veterans, Butler and Lowry, are 32 and 36, respectively, and dealing with nagging leg injuries.

The Celtics are in their fourth conference finals in six seasons; they have yet to win one in this Tatum-Smart-Jaylen Brown era. The 2017 and 2018 appearances were gravy -- youngish teams exceeding expectations, and (in 2018) pushing LeBron James and the Cleveland Cavaliers to the limit.

Then, drama and near misses. Kyrie Irving and Gordon Hayward got healthy in 2019, but the juggernaut-on-paper disintegrated in the second round amid infighting and Irving's wandering eye. The Celtics met Miami in the conference finals the next season in the bubble, losing a six-game heartbreaker that is regarded internally as a painful missed opportunity. They then fell so far as to be a first-round patsy for the Brooklyn Nets. More turmoil followed. Another loss now and regret creeps into the fabric of this core.

Both teams are as well equipped as anyone to defend the whirring Warriors machine, presuming Golden State holds on against the Dallas Mavericks. Boston in particular has played Golden State well over the Steve Kerr/Stephen Curry era. The contender's circle will be more crowded next season.

And though it seems the Celtics have the edge -- they are plus-28 through four games, and have been the league's best team since Jan. 1 -- Miami has home court. Funny things happen in discrete games. One or two variables flipping Miami's way tonight -- Butler's return to form after 14 points on 6-of-22 shooting combined in Games 3 and 4, a scorcher from Herro (if healthy), random foul trouble for Tatum or Brown -- and Miami could be the team up 3-2, with two cracks at the Finals. The Heat reminded us in Game 3 that they are tough enough, stout enough on defense, to finagle a win even with Butler out after halftime. Finagle another tonight, and all the pressure shifts to Boston.