Having lost to the Golden State Warriors 103-90 in Game 6 of the NBA Finals at TD Garden in Boston on Thursday, the Boston Celtics had to watch the opponent celebrate winning the NBA Championship at their home arena.

Before the series began, many had expected the Celtics to win the finals for good reasons. The team could send a five-out offensive scheme to the court with great spacing and keep their advantage in size, power and athleticism. Defensively, they have solid protection of the paint and are able to switch everything, which proved to be one of the best ways to contain the Warriors in recent years.

However, the Celtics failed to turn their theoretical advantages into victory on the floor. Their offensive rating was only 106.6 during the finals, suffering a big drop of 7.8 compared with the team's stats for the regular season. They failed to reach 100 points in four of the six games.

The Celtics were even more disappointing on the defensive category. They allowed only 104.5 points per game during the regular season, the fewest of the league, with the second-best defensive rating of 106.9. Nonetheless, they couldn't stop the Warriors at all, watching Stephen Curry make the best finals performance in his career.

Having averaged 31.2 points, six rebounds, five assists and 5.2 triples at a 3-point rate of 43.7 percent during the series, Curry shot at 65 percent of true shooting percentage when he shot off the dribble exploiting teammates' screen. When he called for screen, the Warriors could score 1.1 points per possession; when he attacked without the ball, the team averaged 1.24 points in each possession.

Celtics head coach Ime Udoka understandably refused to double-team Curry too much because he trusted the isolation defensive ability of his players. However, he underestimated 34-year-old Curry's individual attack in mismatch. Al Horford and Grant Williams were reliable in containing Giannis Antetokounmpo with their strong lower bodies, but they were too slow to follow Curry when he was determined to beat them.

The lost finals also exposed and maximized the Celtics' offensive weak links and the biggest one was the lack of a qualified orchestrator. Marcus Smart's passes were always between highlight and turnover; Derrick White played more like a shooting guard; and Jayson Tatum couldn't read the court correctly unless he drew extra defensive attention first.

When the Celtics ceased to change the Warriors defense via the individual offensive threats of Tatum and Jaylen Brown, their ball movement became too simple and predictable. As a result, the team averaged 16.2 turnovers per game during the finals.

An orchestrator who doesn't compete with Tatum and Brown for ball possessions, has qualified 3-point shooting ability and meets the Celtics' defensive standard, is too expensive for the team to land via trade unless they are willing to change their core roster. With a payroll as big as $151.6 million for the 2022-23 season, the team has no cap space to sign any star free agent.

That's why the Celtics will still need to count on their star duo to improve their offense. Brown can use a better 3-point rate than 34 percent. Moreover, he must expand his offense coverage out of simply charging from the weak side. In order to do that, he needs to improve his dribbling. The Warriors are not the only team that knows to slow Brown down to contain him.

Tatum's situation is more complicated. He was frozen by Andrew Wiggins in the four games the Celtics lost during the Finals but he shouldn't have been obsessed with attacking Wiggins in the first place. The Warriors did a good, but not perfect job of avoiding exposing Curry too often to Tatum in mismatch. It's Tatum who often gave up easily attacking Curry, especially after he couldn't make shots consistently. His mental state affected his free throw shooting as well, which dropped from 85.3 percent in the regular season to 65.6 percent in the finals.

The Celtics are likely to maintain the same squad for the 2022-23 season. They will still be a top team in the Eastern Conference, but their opponents will grow better too as the Milwaukee Bucks have Khris Middleton back and the Miami Heat watch Jimmy Butler and Kyle Lowry recover from injuries.

Despite his underperformance in the lost games of the Finals, Tatum is only 24 years old and just finished his fifth season in the NBA. His growth has been fast and impressive, but the competitions at the top level are cruel enough that he'll have to push himself harder.