The NBA’s defending champions are gone. So, too, is the conference’s No. 1 seed. What might have seemed like the undercard when the East side of the playoffs bracket began now is the main event. If the Miami Heat advance, it will be their first trip to the Finals since 2014. If it’s the Boston Celtics, they’ll be repping the Eastern Conference for the first time since 2010.

There are enough contrasts here to fill several storylines across what figures to be a long series. Boston has an elite level of talent in the backcourt and on the wing, while Miami owes its spot here to tenacity and resourcefulness. The Heat have a deeper and more versatile bench, though the Celtics have done fine using a shorter rotation with heavier minutes loads. Watching Jayson Tatum, Jaylen Brown and Kemba Walker get into the open court can be thrilling, but grinders such as Jimmy Butler, Bam Adebayo and Jae Crowder are happy to play the role of speed bumps. And so on.

Look for added interest with the Raptors, the Bucks and their Coach-of-the-Year winning bosses – Nick Nurse and Mike Budenholzer – gone. Boston’s Brad Stevens has been a genius-in-waiting for a few years now, even as Miami’s Erik Spoelstra has quietly moved into Top 5 or Top 3 status in the league. When the days in between games are as important as the games themselves, providing for tweaks and takeaways as a series plays out, the work of both coaches and their staffs will be on full display.

Three things to watch

1. Is Jimmy Butler good enough? As in, “Can you win an NBA championship if Jimmy Butler is your best player?” This isn’t about picking on Butler – lots of players are put to this litmus test as a way of gauging the strength of a team’s roster. Sometimes it even extends to “… if So-And-So is your second-best player?” Until these playoffs, Butler hadn’t earned affirmative answers to that second question, never mind the first. But he has emerged as a cornerstone guy in the bubble, with as much will as skill, as much tenacity as talent. It would be tough to pick against him as King of the Hill in this series, as far as a total package of ability, leadership, toughness and will.

2. Who are the X-factors for each team? We’re going with Marcus Smart for Boston and Tyler Herro for Miami. They’re a contrast in styles and resumes, with Smart as a forceful, grinding veteran defensive ace and Herro as the lithe, smooth young jump shooter. Smart’s ability to stymie Miami’s backcourt weapons such as Goran Dragic, Duncan Robinson and Kendrick Nunn could be huge, while he gave Toronto some fits with his own 3-point prowess. Herro’s learning curve has been like a fighter jet off the deck of an aircraft carrier, all rapid verticality to become a go-to option at age 20.

3. Will Gordon Hayward return in this series? Hayward, the Celtics’ injury-bugged wing, sprained his right ankle in the opening game of the first round against Philadelphia. His recovery has been slow, but at least he’s out of quarantine. “I think he’ll be back at some point in the series, but I don’t know when,” said Stevens. He has been working with Boston’s training staff while still not cleared for full contact. If he comes back at anything close to his regular-season form (17.5 ppg, 6.7 rpg, 4.1 apg, 50 percent shooting), he’ll give the Celtics yet another weapon to stress Miami’s defense.

Number to know

10.5 — In their five-game series against the Milwaukee Bucks, the Heat scored 10.5 more points per 100 possessions (113.0) than the Bucks’ top-ranked defense allowed in the regular season (102.5). That was, by far, the biggest such offensive differential in the conference semifinals.

In their seven-game series against the Toronto Raptors, the Celtics allowed 10.5 fewer points per 100 possessions (100.3) than the Raptors scored in the regular season (110.8). That was, by far, the biggest such defensive differential in the conference semifinals.

The Heat ranked second in 3-point percentage (37.9%) in the regular season and rank third (38.0%) in the playoffs. The Celtics ranked second in opponent 3-point percentage (34.0%) in the regular season and rank first (30.5%) in the playoffs.

So it will be strength vs. strength on Miami’s end of the floor. Boston ranked second defensively (106.3 points allowed per 100 possessions) among Eastern Conference teams against Miami in the regular season, and the Celtics’ December win was one of only seven times this season that the Heat were held under a point per possession. But Miami had a big offensive game (without Jimmy Butler) when the two teams met in the restart, taking 43 (56%) of their 77 shots from 3-point range and scoring 112 points on just 95 possessions.

— John Schuhmann

The pick

Boston took two out of three meetings in the regular season, though the only meeting since Feb. 1 went Miami’s way in the bubble Aug. 4. Of greater impact, possibly, is the week of rest the Heat will have earned by the time the East finals begin – that was Miami’s reward for not merely upsetting the favored Bucks but doing so in five games. Boston had to labor hard to the final minutes of a Game 7 to eliminate the Raptors. But three days to rest and prep, without any travel fatigue, should be enough. Besides, this round isn’t going to be a quick knockout for anybody. Miami’s full embrace of the idea they’ll control their fate, and the defenders they’ll attach to the Celtics best scorers, favors sweat more than style. Heat in 7 .

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Steve Aschburner has written about the NBA since 1980. You can e-mail him here, find his archive here and follow him on Twitter.

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