Much like the Boston Red Sox 19 years ago, the Boston Celtics brought a seemingly unwarranted confidence into Game 4 against the Miami Heat.

Down 3-0 in the series, the Celtics told the world to watch out if they got one win to stay alive.

The Celtics got that Game 4 win. And their odds to win the series, while still not great, are looking a lot better. Winning the series looks somewhat realistic now.

The Celtics, who were +750 to win the Eastern Conference finals on Tuesday afternoon at BetMGM, are all the way down to +225 after the Game 4 win.

The first 150 times an NBA team took a 3-0 lead in the series, that team won the series. The 151st time has some intrigue now.

Celtics favored in Game 5

The Celtics go home for Game 5 as 7.5-point favorites. The Heat already won in Boston as 8.5-point underdogs in Game 1 and 10-point underdogs in Game 2, so it's not like being a big favorite is the final say in who wins Game 5. But the Celtics' path to history is a lot clearer after getting that one win that Marcus Smart and Jaylen Brown warned everyone about.

The Celtics are significant favorites in Game 5. If they win that, they'll have two straight wins, a lot of momentum and will likely be favored in Game 6 even though it's in Miami. The Celtics were 4.5-point favorites on the road in Game 3, even though they lost the first two games of the series. And Boston would be a big favorite again at home in a Game 7, if it can extend the series that far.

Being a favorite doesn't mean much in the conference finals this year — underdogs are 8-0 against the spread this round — but the Celtics will likely be favored in every game the rest of this series.

That's a rare spot for a team that was down 0-3.

Can Celtics make history?

In 2004, Red Sox first baseman Kevin Millar had a mic'd-up clip before Game 4 of the ALCS against the New York Yankees in which he laid out the path for his team to come back from an 0-3 series hole. Millar kept repeating that they just needed to get one win, then they'd have Pedro Martinez and Curt Schilling pitching in the next two games, and anything could happen in Game 7. When the Red Sox became the first (and still only) MLB team to come back from 0-3 down, that clip became famous in Boston.

Baseball is a much different sport than basketball. But the message sure seems similar from the 2023 Celtics.

There's still a long way for the Celtics to go. The Heat won't be scared of being an underdog in Boston; they've won twice in that spot. The Celtics have had perplexing home losses in all three rounds of the playoffs. This is not a dominant Boston team. It shouldn't shock anyone if the Heat win any of the next three games.

That's why, even though Boston will probably be favored in the final three games of the series, the odds of them advancing are +225. There's still a hill to climb. But those odds aren't too bad considering the 0-150 record of those teams that were in the Celtics' position before this year's Eastern Conference finals.