The 2023 NBA All-Star break is officially upon us, and at the break, the team with the best record in the league is the Boston Celtics. The Celtics have a 42-17 record, and have been in control atop the Eastern Conference for much of the season. While the Milwaukee Bucks are sitting just a half-game behind them, it feels like the C's are in the driver's seat when it comes to finishing as the number one seed in the East.

Boston has taken the league by storm despite dealing with a rash of injuries and controversies along the way. Key players such as Marcus Smart, Robert Williams III, and now potentially Jaylen Brown, have missed extended periods of time with injuries, and they only recently made Joe Mazzulla their newest head coach after he was tasked with replacing Ime Udoka, who was suspended for the entire season by the C's.

From a roster building perspective, the Celtics don't necessarily have a fatal flaw anymore after they acquired Mike Muscala at the trade deadline. And in terms of their play on the court, Boston doesn't have a glaring weakness. Still, there's one interesting flaw that occasionally comes back to bite them, and if it doesn't get fixed, it could disrupt their title run for the second straight season.

Celtics fatal flaw: Clutch time offense

Throughout the Jayson Tatum/Jaylen Brown era in Boston, we have watched a young Celtics team grow in front of our eyes, and in the process, overcome many of the issues that once plagued them. Their offense doesn't rely heavily on isolation sets and contested mid-range jumpers, their rebounding has vastly improved, and they have the depth on their roster to support their star players.

The one area that Boston has still struggled with to an extent this season is their offense in clutch situations. Clutch time in the NBA comes in the final five minutes of the game when the scoring margin is within five points, and for whatever reason, the Celtics offense always seems to become stagnant when the game reaches these situations.

Now, in terms of the statistics themselves, they are vastly improved from previous iterations of the Celtics. Their 113 offensive rating in clutch situations is fifth best in the league, and when you factor in their defensive rating of 100.9 in these situations, their net rating of 13.7 is the third best mark in the league.

It may not seem like this is a flaw at all, but Boston has only played in 26 games where clutch time has come into effect, which is the fourth lowest total in the league. And for the most part, the Celtics have simply turned things up a notch and put the game to bed after toying with their opponent. That's a luxury you have in the regular season, but not necessarily the postseason.

Just last year we saw the Golden State Warriors stifle the Celtics offense in the NBA Finals and go on to win their fourth championship in eight years. The two games that flipped the series on their head (Games 4 & 5) saw the Celtics score just 39 combined points in the fourth quarter. Boston had a five-point lead with seven-and-a-half minutes left in the fourth quarter of Game 4, but only managed to score six more points the rest of the way out.

In these late game situations where the game is close, the Celtics continue to fall into their bad habits for stretches of time. We have seen it happen on a couple of occasions this season, where they prefer to let Tatum or Brown run down the shot clock in an isolation set before settling for a tough shot. Depending on the situation, it's not an awful strategy, but in these clutch situations, it results in losses piling up.

The good news for Boston is that their team has the talent to overcome this flaw, which wasn't necessarily the case in previous seasons. Tatum and Brown are two of the best isolation scorers in the game, and considering the personnel around them nowadays, it makes it a lot tougher for opposing defenses to throw more bodies in their way without getting burned.

So far in the regular season, it hasn't hurt them much, but there are worrying underlying signs that this could be an issue that pops up again down the line, especially in the playoffs. This is easily the most talented Celtics team we have seen in awhile, but it's fair to wonder if they will wither away late in close games again in the postseason.

The fix is pretty simple, and it would result in Boston just sticking to their guns on offense. Obviously you want your best players taking the biggest shots, but Boston should realistically feel good about any of their top eight or nine players taking big-time shots. If the Celtics don't fall back into their old habits late in the fourth quarter of close games, they will be extremely tough to beat. But if they do, this could end up being the fatal flaw that destroys their season.