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Believe or not, the hard part is already done for the Boston Celtics. In NBA history, 150 teams have built a 3-0 lead in a seven-game series. Of those 150 teams, 136 went on to win their matchups in five games or less. That means that more than 90% of teams facing 3-0 deficits before the 2023 Eastern Conference finals got knocked out faster than the Celtics have. Historically speaking, teams trailing 3-0 almost never make it to 3-2.

But 3-2 deficits are nothing new to the Celtics. They overcame one last round against the Philadelphia 76ers. They did so a year ago against the Milwaukee Bucks. A 3-0 deficit is NBA history, but a 3-2 deficit is par for the NBA course. In all of NBA history, there have been 342 series in which one team trailed 3-2, and 55 of those teams went on to win the series. That's a win rate of 16.1%. Not a big number by any means, but not the 0% historical fact of the deficit Boston faced just four days ago. Vegas gives Boston a much better shot than 16.1%. At Caesar's Sportsbook, the Celtics current have a plus-118 line to win the series. Those are implied odds of 45.87%.

At worst, the Celtics have an outside chance to make history. At best? This thing is a coin flip. That notion defies eight decades of NBA history, so let's dive into the teams that almost pulled off the impossible comeback and figure out what kind of chance the Celtics really have to win this thing and reach the NBA Finals for a second straight season.

The six-game losers

NBA history has seen 11 teams turn a 3-0 lead into a 4-2 series loss. Those teams, in chronological order, are:

  • The 2022 Toronto Raptors, who lost to the Philadelphia 76ers in the first round.
  • The 2015 Milwaukee Bucks, who lost to the Chicago Bulls in the first round.
  • The 2013 Houston Rockets, who lost to the Oklahoma City Thunder in the first round.
  • The 2013 Boston Celtics, who lost to the New York Knicks in the first round.
  • The 2010 Orlando Magic, who lost to the Boston Celtics in the Eastern Conference finals.
  • The 2007 Chicago Bulls, who lost to the Detroit Pistons in the second round.
  • The 2000 Philadelphia 76ers, who lost to the Indiana Pacers in the second round.
  • The 1996 Seattle Supersonics, who lost to the Chicago Bulls in the NBA Finals.
  • The 1962 Detroit Pistons, who lost to the Los Angeles Lakers in the Western Division finals.
  • The 1949 Washington Capitols, who lost to the Minneapolis Lakers in the NBA Finals.
  • The 1947 Washington Capitols, who lost to the Chicago Stags in the semfinals.

Let's immediately rule out those last three teams for having played in a completely different NBA. The other teams all played within the past three decades. So what are our commonalities? There are two pretty big ones, and they make sense: only two of the eight series came in the last two rounds, and only one of the eight teams to fall behind 3-0 was the higher seed. All of this stands to reason. A series is typically likelier to be close later in the playoffs as the overmatched teams have been knocked out, and the team with the better regular-season track record is likelier to be the one building that 3-0 lead.

So how did those teams that built their 3-0 leads stumble? In most cases, we can point to a single, isolated explanation. Joel Embiid tore a ligament in his thumb during Philadelphia's Game 3 win over Toronto in 2022. A dirty play by Patrick Beverley in 2013 ended with Russell Westbrook tearing his meniscus during Game 2 of that Thunder-Rockets series. The 2013 Knicks played Game 4 against Boston without their second-leading scorer, J.R. Smith, who got suspended for a Game 3 scuffle with Jason Terry. He returned for Game 5, but shot 3 of 14. The 1996 Sonics famously changed their defense going into Game 4 of the Finals against the Bulls, allowing hobbled Defensive Player of the Year Gary Payton to guard Michael Jordan. Had they done so from the start, they might have won the series.

In other cases, the shift, and really the series as a whole, simply came down to a few bounces. The 2010 Eastern Conference finals were a perfect example of this. Games 1, 2 and 4 were all decided by four points or less -- and all four were won by the road team. The two teams were relatively close all along, but the ball happened to bounce Boston's way early in the series and Orlando's way late. On a similar note, shooting luck frequently hampers superior teams. The 2000 Pacers shot 10 of 41 from deep in Games 4 and 5 against the 76ers after leading the league in 3-point percentage during the regular season. Sometimes good teams just get cold.

But generally speaking, a team that is good enough to build a 3-0 lead over a lower seed is usually good enough to win one out of their next three games even when they've stumbled for one reason or another.

The seven-game losers

We've seen far fewer teams turn a 3-0 deficit into a winner-take-all Game 7. That has only happened three times in NBA history:

We will again ignore what happened in the 1950s to focus on the two more contemporary examples. The trends we covered above held here. Both the 2003 Blazers and 1994 Nuggets mounted their attempted comebacks in the first two rounds, and both did so as the lower seed. That last detail is critical. It means that for the Blazers and Nuggets to win Games 4, 5 and 6, they only needed to win on the road once. That made their task far more manageable. Both lost Game 7 on the road, which is the norm in the NBA, as home teams win roughly 80% of winner-take-all matchups.

The 2003 series between the Blazers and Mavericks was remarkably simple once you look at the box scores. The team that made more 3-pointers won Games 1-6. The Mavericks managed to buck this trend in Game 7 by hitting just seven long-range shots to Portland's nine, but the Blazers shot a laughable 26 of 63 against an underwhelming Dallas defense inside of the arc to blow the game. The Blazers actually led Game 7 going into the fourth quarter, but lost the final frame by 14 points because three Dallas players got hurt. Nick Van Exel, Steve Nash and Dirk Nowitzki combined to score 31 points in 11 minutes to seal the series for the Mavericks.

The Jazz-Nuggets series looks a bit more like the 2010 Magic-Celtics matchup. Games 3, 4 and 6 (the three games played in Denver) were all decided by a single possession. Utah won the first. Denver won the next two. Again, Game 7 came down to the stars. Karl Malone scored 13 more points than anyone else on the floor, and the Jazz won by 10 at home. John Stockton was also dealing with a thigh bruise he sustained in Utah's first-round win over San Antonio, but he played in all seven games.

So, again, we have matchups that hit a couple of our key trends. The 2003 series swung on shooting variance. The 1994 series came down to a couple of bounces in close games. So what's going on with the Celtics and Heat?

Why Boston can make history

The Celtics already have a chance to buck one major trend here. Of the 10 modern era teams to go from 3-0 to 3-2, only one (the 2010) Magic, were the higher seed. The Celtics are the higher seed. If they can win Game 6 on the road Saturday, then two nights later they will become the first team in NBA history to go from a 3-0 deficit to hosting a Game 7.

Their own postseason suggests that have a strong chance of doing just that. The Celtics actually have a better road record this postseason (5-3) than home record (5-5). During the regular season, Miami's home record (27-14) was barely better than Boston's road record (25-16). The Celtics had a better net rating on the road (plus-3.3) than the Heat did at home (plus-1.1). All of this is to suggest that while the Heat may be at home for Game 6, their advantage is likely to be minimal. The road Celtics and home Heat are of fairly similar quality as teams.

Those regular-season numbers aren't even fully accurate. The Heat are an entirely different team now. Tyler Herro and Victor Oladipo are out. Breakout point guard Gabe Vincent missed Game 5, and his status for Game 6 isn't clear due to a sprained ankle. The Celtics have injuries too, such as the torn tendon in Malcolm Brogdon's arm, but it seems as though Boston has adjusted by shifting more minutes and shots to Marcus Smart and Derrick White.

Similarly, it's worth wondering if Jaylen Brown might have dealt with some pain after seemingly dealing with a minor elbow injury chasing a loose ball in Game 1. He didn't top 17 points in Games 2-4, and more importantly, shot just 2 of 19 from deep. In Game 5, however, he scored 21 points and made three of his five 3-point attempts.

Variance on 3-point shots has been one of the major themes of Miami's postseason. The Heat ranked 27th in the NBA in regular-season 3-point shooting, making just 34.4% of their looks. They went on to make 45% of their attempts in their first-round upset over the Bucks, and then hit just under 48% in Games 1-3 against the Celtics. Boston, meanwhile, ranked sixth in the NBA in 3-point percentage in the regular season by hitting 37.7% of their shots. But in Games 1-3, they hit 29.2% of their 3's. This is especially important in this series because the Celtics took the second-most 3-pointers in the NBA during the regular season, but attempted the sixth-fewest shots in the restricted area. Their whole offense relies on making 3's.

Extreme variance is baked into modern basketball. Shot diets are weighted so heavily towards 3-pointers that plenty of series simply come down to which team gets hot on the right nights. Ultimately, trying to predict whether that will be the Heat or the Celtics in Games 6 and/or 7 would be pointless. But the conditions for a comeback are in play in this series. Both teams are starting to play more like their regular-season selves, and for the first six months of the season, the Celtics were the far better team. If they can keep that up for two more games, they'll have a chance to make NBA history.