Former Boston Celtics guard and current studio analyst Eddie House was clearly a bit upset following the Boston Celtics’ 117-109 loss to the Orlando Magic back in December.

On the Celtics’ postgame show, he unartfully blasted the Celtics for the loss to the then-lowly Magic. This was not a game the team could lose. They could not sleepwalk through any game, especially against a team they should beat like the Magic. These were losses they would regret.

Magic fans, of course, listened to the insult. The clip of the criticism made its way to the locker room and the young team seethed at not getting credit for the win.

The fact they had another game and beat the Celtics a second time 95-92 to finish off a six-game win streak only made everyone on either side double down — those GIFs from the 2009 series were a lot of fun.

For the Celtics though, those words from House said back in December sure feel prescient now.

The Boston Celtics always had a problem with keeping their focus and finishing off weaker opponents. Their inability to play in discomfort cost them a trip to the Finals.

House was perhaps overlooking the Magic — the Magic had not earned their keep in the league quite yet despite the win streak they were on back in December — but he was making a point about the team he was covering. He was making a statement of something the Celtics would need to change if they were going to step up and win a championship.

The Celtics played down to their opponent for sure. They did not play with the same championship-level attention to detail or aggression.

Perhaps more alarmingly for Boston and its future, as it tries to get over the hump and win the championship with this group, they looked unable to take that punch. They crumpled and never got themselves right.

The fact this happened repeatedly during the playoffs was a sign of a clear weakness in the team. Something that the Magic were not the first to expose but did so in December.

When the chips were down, the Celtics were never comfortable being uncomfortable. They constantly struggled to close out games throughout the playoffs. When teams laid that first punch on them, they seemed to panic and abandon their principles and what worked. They struggled to get themselves playing the right way.

When Boston plays well, the team is capable of winning a championship. When the Celtics are not, they are frustrating to watch and just feel like empty calories. And there is not really any medium ground.

Sitting here a few days after the Celtics’ stunningly bowed out of the Eastern Conference Finals in seven games, having rallied from down 3-0, that prediction from House felt prescient.

The Miami Heat were never a team to overlook even as an 8-seed. But Boston again looked like the team overlooked its opponent. It played like it did against Orlando as if it could reach into its reserves and win the game.

Against a quality opponent, that just does not work.

The Celtics were just 5-6 in clutch situations. But they had some significant failures — a Game 5 loss to the Atlanta Hawks that sent them back on the road to close out that series and blown leads late in Games 1 and 2 of the Eastern Conference Finals against the Miami Heat — that characterize this struggle. They never felt comfortable or confident late in games.

It was the series against the Heat though that exposed this weakness.

This series was all about the Celtics’ mistakes. Miami is simply a team that mucks everything up and makes its opponents uncomfortable. The Heat take advantage of every mistake and bet their discipline and execution will beat you late in games — they are 6-3 in clutch situations in the playoffs, a clear sign of their poise and their ability to flip games in their favor.

Boston though kept making mistakes. The Heat’s defensive scheme put the Celtics constantly on their back foot. It forced Boston to settle for threes — Boston shot 30.3 percent from beyond the arc on 38.1 attempts per game after shooting 37.7 percent on 42.6 attempts per game.

The Celtics were always a team that lived and died by its 3-point shot. The quality of those 3-pointers was the real question. And it just felt like Boston settled for threes as Jayson Tatum and especially Jaylen Brown struggled to get in the interior and score consistently.

Neither of the Celtics’ star players seemed able to take the heat. And their offense devolved into passes around the perimeter as they struggled to drive against the Heat’s switching defense or into isolation plays, which just plays in the Heat’s push for turnovers and pressure defense.

In the end, it just looked like Boston could not figure out how to solve the puzzle. The Playoffs are about beating an opponent that knows everything that is coming and making that play that still beats it or that adjustment that cracks that gameplan open.

Flexibility in your attack is clearly important. But it is just as important to be able to play and succeed when you are uncomfortable.

Most successful playoff teams will flirt with disaster in some way. The postseason exposes a team’s every flaw and the question each team has to answer is what it will do to cover for that flaw or overcome it.

One play or one game can literally turn a successful season and every successful team is going to have to thrive while being uncomfortable. The teams that are best at facing this adversity and coming back from it or playing well despite this discomfort are the teams that succeed.

This is, of course, central to the Heat’s culture.

To the Celtics? It was clearly something they could not reach down and grab. They got staggered in this series and never could find their center. Or they could not find it long enough.

Unfortunately for a young team like the Magic, it is hard to know how the Magic will play when they are uncomfortable.

They have shown signs their culture can withstand this and lock back in. They could have easily quit when they were 5-20 this past season. To rally the rest of the season to stay in the postseason chase and get to 34 wins was a sign of their potential and their buy-in to the culture they are building.

But that is not playoff pressure. The Magic are going to have a moment in their first playoff run where the moment seems too big or the opponent too tough. And nobody knows how this team and this group will respond to it.

They are likely to fail that first time too. There are still lots of experiences to gain for this growing team.

But playoff success is dependent on how a team plays when they are uncomfortable and things are not going well. They have to have the faith and trust to keep grinding and keep fighting.

That is where the Celtics failed miserably in their Eastern Conference Finals series. And a lesson for the rest of the league.