CLEVELAND, OH – MAY 21: Al Horford #42 celebrates with Jonas Jerebko #8 of the Boston Celtics after their 111 to 108 win over the Cleveland Cavaliers during Game Three of the 2017 NBA Eastern Conference Finals at Quicken Loans Arena on May 21, 2017 in Cleveland, Ohio. NOTE TO USER: User expressly acknowledges and agrees that, by downloading and or using this photograph, User is consenting to the terms and conditions of the Getty Images License Agreement. (Photo by Jason Miller/Getty Images)

Seemingly all throughout the 2017 NBA postseason, it’s been a formality that the Cleveland Cavaliers and Golden State Warriors would meet for the third consecutive year in the NBA Finals. And for the vast majority of the playoffs, it looked like both would reach the Finals by incomprehensibly going 12-0 and sweeping every single round along the way.

Those hopes of a 12-0 Cavs vs 12-0 Warriors showdown were dashed by maybe the most unlikely reversal in NBA Playoffs history. The Boston Celtics — after losing Game 2 at home by 44 points and without their best player Isaiah Thomas — somehow found a way to win on the road in Cleveland, 111-108, thanks to an Avery Bradley buzzer-beater.

Just two nights before, the Celtics were embarrassed on their home floor by the Cavs like maybe no team had ever been before in the postseason. Cleveland built up the largest halftime lead in playoff history with a 41-point lead going into the locker room, thanks to this acrobatic J.R. Smith shot.

The fact that the Celtics showed up at all in Cleveland and played competitively was surprising enough, especially when they could have packed it in after falling behind by double digits once again. It’s been a great year for the Celtics. “Conference finals berth” plus “No. 1 overall pick” is enough to make any franchise satisfied with their progress. Give them all the credit in the world for winning as 17-point underdogs in one of the biggest upsets in recent postseason memory.

In the short term, the Game 3 result isn’t likely to change the course of the Cavs-Warriors showdown. These were the Cavaliers we saw in the regular season, all too willing to let their foot off the gas pedal and coast down the stretch by blowing a big lead. And maybe that’s natural because it’s been all too easy for Cleveland thus far. How could complacency not kick in when you destroy the opposition on their home floor by 40+ points? Even Golden State had to get through a major comeback in Game 1 against the Spurs, and a massive dose of luck with Kawhi Leonard’s injury, on their way to a 3-0 lead out west.

On top of that attitude entering into the equation, LeBron James had a rare off night in Game 3 with just 11 points. You know he’s going to come back with a vengeance in Game 4 to make sure his team gets back on track before their eventual matchup with Golden State.

And furthermore, it’s one thing for Boston to steal a game against the Cavaliers. But they still have to win three more games out of four without their best player. As unlikely as their Game 3 triumph might have been, imagine what the odds would be of actually coming back to win this series.

However, I’d argue that the impact of Boston’s Game 3 victory over Cleveland is much more important for the psyche of the Celtics franchise in the long-term than in the short-term.

(Photo by Jamie Sabau/Getty Images)

It was painfully obvious in the first two games of the series that the Celtics had far, far, far, far too much respect and deference for the Cavaliers. It was almost like they completely forgot they had actually won the Eastern Conference during the regular season and deserved to be on the same floor. These young Celtics have grown step by step with Brad Stevens and improved their record every season.

But in Games 1 and 2 of the ECF, the Celtics played like they were a couple years ahead of their grand rebuilding project. They played like they weren’t ready for the moment and they failed to match the intensity and the execution of the Cavaliers. The best way to describe their play was “awestruck.”

At that point, heading to Cleveland down 2-0 and getting so thoroughly demolished on their home floor, the easiest thing in the world to do would have been for the Celtics to mentally cash in their chips and look ahead to next season. After all, the Celtics weren’t realistically supposed to challenge the Cavaliers this season, even with the addition of Al Horford.

With Jaylen Brown still developing as a rookie and Markelle Fultz likely on the way, this is a team that should be reaching its peak in two to three years when LeBron James is at the tail end of his run in Cleveland. Not in 2017 when he’s still very much in his prime. (Of course, with this being LeBron James we’re talking about, his prime could stretch into 2037.)

Imagine, though, how hard it would be for Brad Stevens to convince his team that they could compete with Cleveland if they had lost by 20 points every game this series. If they could never come close to beating the playoff version of the Cavaliers (forgetting the regular season), it would have made the mental hurdle to climb much taller than the physical hurdle. The kinds of defeats the Celtics suffered in Game 1 and especially in Game 2 can be demoralizing to any franchise no matter how far ahead of schedule you think you might be.

If anything, the Game 3 victory and buzzer beater by Avery Bradley shows this young Celtics bunch one thing: “We can actually beat these guys.”

That kind of confidence and self-belief can only be established with experience. And maybe most importantly, it can only be established with the experience of actually stepping onto the court and winning. It may not change this 2017 Eastern Conference Finals series at all.

But with a healthy Isaiah Thomas and the No. 1 pick in the fold next year, it would hardly be a surprise to see a Boston-Cleveland rematch in the Eastern Conference Finals next year. And whatever else happens in this year’s series, the Celtics will go into that matchup knowing that somehow, somewhere, they have what it takes to beat the Cavaliers.