Boston Celtics' Kyrie Irving (11) and teammates, from left to right, Jaylen Brown, Marcus Morris, Jayson Tatum and Gordon Hayward wait for the ball to be put in play by the Milwaukee Bucks on Monday during the second half of Game 4 of a second-round NBA basketball playoff series in Boston. Credit: Michael Dwyer | AP

Not quite two years ago, Kyrie Irving and the Boston Celtics came together with the best of intentions.

The superstar point guard sought greater fame, a franchise to call his own and an escape from LeBron James’ shadow. The storied franchise needed a healthier lead scorer than Isaiah Thomas, an injection of championship experience and an established veteran who could mentor young prospects and potentially lure other A-list stars.

This was more than a marriage of convenience. The Celtics offered Irving better organizational structure, a stronger history of winning and a better coach than the teams that appeared on his wish list when he demanded a trade from the Cleveland Cavaliers.

Irving was one of the league’s most popular, marketable and electric playmakers — exactly the type of player that Boston had desired, and struggled to attract, in free agency.

Their union was put to the test for the first time this week, and it failed spectacularly.

Irving, fresh off eight months of braggadocious declarations about his ability to single-handedly solve the Celtics’ problems, crumbled to pieces against the Milwaukee Bucks. The self-styled “basketball genius” played well in just one of the Celtics’ five games against the East’s top seed, and his influence waned as the series unfolded.

Once the dust and the emotions settle, both Irving and the Celtics should come to the same conclusion: they are better off without each other.

Milwaukee was a better and more complete team than Boston, armed with the best player in the series: Giannis Antetokounmpo. But Irving’s poor play in the series ranged from baffling to inexcusable.

In Game 2, he scored just nine points — the second-lowest total of his postseason career. In Game 3, as Antetokounmpo seized control of the series, Irving shot 8 of 22 and railed against the referees mere minutes after Celtics Coach Brad Stevens said the officiating was not to blame for Boston’s woes.

In Game 4, Irving shot 7 of 22 and comically tried to take on defensive responsibilities that were well beyond his limited capabilities. After leaving the TD Garden court to boos from the home crowd, he delivered the least satisfying response to questions about his struggles: “Who cares?” Finally, in a series-deciding Game 5 blowout loss, he checked out completely, going down in a blaze of hero ball shots and mental lapses.

Worst of all, Boston took on the identity of its franchise player along the way. Last year, with Irving sidelined with a knee injury, Boston emerged as a tenacious underdog in the playoffs, improbably winning two series and pushing James’ Cavaliers to seven games in the conference finals.

This season, Boston was maddeningly inconsistent and arguably the NBA’s biggest disappointment. The first hint of postseason adversity broke the Celtics, who quit on each other down the stretch of Game 4. Ball movement on offense and extra effort on defense disappeared entirely, replaced by shrugged shoulders and pointed fingers.

This postseason confirmed the assumption that Irving isn’t equipped to be the first option on a true title contender. In Cleveland, he thrived as a second option, utilizing his exquisite ball handling and isolation scoring skills to roast defenses that had to focus most of their attention on James. When Irving was faced with traps, extra attention and the pressure to deliver play after play, he wasn’t up to the task.

Boston’s offense ranked just 12th in the playoffs after Game 5, and Milwaukee was happy to trade Antetokounmpo dunks and wide open threes for Irving’s contested long twos. The Bucks bet that Irving would become overly self-reliant and that he couldn’t make enough good decisions as a passer. They were right.

Irving’s defenders will point to a decided lack of help from a supporting cast that wavered in this series. Fair enough, but Irving hardly cultivated a cohesive culture this season and his confidence in his teammates’ quickly waned in the playoffs.

While the Celtics have numerous attractive trade assets, it’s difficult to envision a path where they can acquire a star playmaker this summer who can shoulder the burden that proved to be too heavy for Irving. Their cap is also weighed down by Gordon Hayward’s gigantic contract and the need to pay Al Horford if he opts out. What’s more, Irving hardly developed rapport with Boston’s two most promising youngsters: Jayson Tatum and Jaylen Brown.

Irving has some options: he could attempt to pursue a partnership with Kevin Durant in New York, he could swallow his pride and hitch a ride to James’ Los Angeles Lakers, or he could take a second shot at being “The Man” for the Brooklyn Nets or Los Angeles Clippers. Any of those options would enable him to start fresh, leave the burned bridges in Boston behind and walk into more flexible cap situations.

The Celtics are better off without Irving, too. While he was undoubtedly their best player, their team structure required him to rise to the moment and pull the team over the top. The opposite happened, as Boston won 10 playoff games over two years with Thomas running the show and just five with Irving on the court during his two-year stint.

Clearly, Boston finds itself at an unexpected crossroads. Trying to run it back makes little sense, given Hayward’s long-term health questions, Horford’s advancing age and the fact that Irving didn’t make Tatum and Brown appreciably better. One could argue that Irving’s presence and ball dominance actually played a role in stunting their growth.

Moving on from Irving would create more oxygen for Tatum and Brown, and it would relieve the expectations that swallowed this year’s team. Stevens would then be free to return to a more egalitarian offensive approach and a more fearsome commitment to team defense.

Not to be lost in Boston’s long-term thinking is Irving’s health and his positioning relative to his peak, as the 27-year-old guard is slated to receive four-year max offers despite already enduring multiple season-ending injuries. Irving remains one of the quickest and most dynamic players in the league, but he’s never played in more than 75 games in any of his eight NBA seasons. He’s also theoretically at or near his prime, from an age perspective, so hoping that he will come back next season as a substantially more effective postseason player is just asking to be let down.

One of the toughest things is to know when to cut one’s losses, especially after investing years of time and mental energy. It was telling, then, that Irving couldn’t wait to get off the court following the Game 4 loss, to escape the mess that he didn’t see coming and couldn’t solve as he had promised.

The Celtics should let him keep walking.