The Boston Celtics' historic season came to a stunning conclusion on Sunday night, as they became the first team in franchise history to blow a 3-1 series lead. The Philadelphia 76ers completed their improbable comeback with a 109-100 victory in Game 7 at TD Garden, leaving the home crowd in disbelief.

For the Celtics, who had dominated the regular season and looked poised for a deep playoff run, the loss was a bitter pill to swallow. But if you expected panic or despair in the locker room afterward, you'd be mistaken. Instead, Boston's players and coaches maintained a remarkably steady demeanor, focusing on the bigger picture.

"We stick to the process," said Jaylen Brown, who carried the offensive load in the absence of injured star Jayson Tatum. "Great season. Obviously, it didn't finish the way we would've liked. I give credit to Philadelphia. I watched them get better as the series went on. But just for our guys to come out in a Game 7 and play with that level of intensity and trust, that's the style we felt like we've been doing all year, and I loved it."

The Celtics were dealt a major blow just an hour before tip-off when Tatum was ruled out with left knee stiffness. It marked the first game he had missed due to injury since his remarkable comeback from a ruptured right Achilles tendon last May. Without their leading scorer, coach Joe Mazzulla was forced to get creative, rolling out a starting lineup of Brown, Derrick White, Baylor Scheierman, Luka Garza, and Ron Harper Jr.—a combination that had never played together all season.

The makeshift lineup struggled out of the gate, as the 76ers jumped to a 30-15 lead in the first quarter. Despite a valiant effort to claw back, Boston never fully recovered, and Philadelphia's bench—led by Tyrese Maxey and Joel Embiid—celebrated their stunning series win on the Celtics' home floor.

For a team that had won 32 straight best-of-seven series after taking a 3-1 lead, this loss stings. But the Celtics aren't dwelling on the past. Instead, they're choosing to focus on the foundation they've built, trusting that the process will pay off in the long run. As they head into the offseason, that steady mindset might be their most valuable asset.