Celtics vs 76ers 2026 Playoffs: How Boston Blew a 3-1 Lead – And What They Must Do This Offseason

NBA Playoffs Analysis · May 2, 2026

By HooperClass  ·  May 2, 2026  ·  9 min read  ·  NBA

They had a 3-1 lead. They had home court. And they had every reason to believe this series was over. Then Jayson Tatum’s knee gave out, Joel Embiid got motivated by a careless comment, Tyrese Maxey took over in the fourth quarter of Game 7 — and just like that, the Boston Celtics’ season was over. Again.

The 76ers overcame a 3-1 series deficit and knocked off the Celtics 109-100 in Game 7 on the road at TD Garden , booking a second-round matchup with the Knicks. It was one of the most dramatic collapses in recent playoff memory — and it raises serious questions about where Boston goes from here.

How the Series Went

Boston won Game 1 comfortably, 123-91, looking every bit the contender they were seeded to be. Tatum was dominant, the defence suffocated Philadelphia’s offence, and everything seemed under control. The Celtics built a 3-1 series lead and were one win away from the second round.

Then Joel Embiid returned from a 7-game absence due to an emergency appendectomy , and the series completely flipped. Philly outscored Boston 62-40 over the middle two quarters of Game 6 and forced Mazzulla to pull his starters with over 10 minutes left in the fourth. Tatum hurt his leg in that game and never looked the same.

On Game 7 day, the Celtics ruled Tatum out 90 minutes before tip-off with left knee stiffness — forcing Boston to start Ron Harper Jr. and Baylor Scheierman alongside Derrick White, Jaylen Brown and Luka Garza. Without their best player, the Celtics had no answer for Embiid and Maxey.

✅ Boston’s Strengths This Series

Tatum when healthy was elite. In six playoff games before the injury, Tatum averaged 23.3 points, 10.7 rebounds and 6.8 assists while shooting 47.5% from the field. He was the best player in the series until his body gave out — and it showed what this team can be when he’s fully fit.

The depth was real. The Celtics spent the first three-quarters of the season without Tatum as he recovered from his Achilles, and still finished as the No. 2 seed in the East. Jaylen Brown, Derrick White, and Payton Pritchard kept this team functioning at a high level all season — and that’s genuinely impressive.

Mazzulla’s coaching. Brad Stevens won his second career NBA Executive of the Year award after assembling the roster for Boston’s 56-win team. Mazzulla got the maximum out of a squad missing its best player for most of the year — that deserves credit even as the season ends in disappointment.

❌ Boston’s Weaknesses This Series

The three-point shooting collapsed. In the regular season, the Celtics were 38-5 when they shot 36% or better from three — but 18-21 when they didn’t. In the final three games of this series, their shooting went ice cold, and they had no Plan B when the threes weren’t falling.

Payton Pritchard’s comments were unforgivable. Pritchard said before Embiid’s return that he didn’t care if Embiid was playing and that the Celtics hadn’t adjusted their game plan around him — a statement that gave Embiid exactly the motivation he needed. Embiid scored 34 points in Game 7 and publicly called out Pritchard after. That kind of bulletin board material in the playoffs is inexcusable.

No closer without Tatum. When Tatum went down, the Celtics had no one capable of creating their own shot in crunch time. Jaylen Brown was the best option — but Brown in a Game 7, on the road, without his co-star, against Embiid and Maxey firing on all cylinders, was always going to be a very difficult ask.

Tatum’s injury management was questionable. Tatum ruptured his right Achilles tendon just last May and was less than 12 months removed from surgery when this series started. His minutes jumped from 32.6 in the regular season to 36.3 in the playoffs. With a player coming back from that kind of injury, protecting him more aggressively in the regular season — and potentially even Game 6 — might have changed everything.

What the Celtics Must Do This Offseason

1. Get Tatum fully healthy — and keep him that way. This is the only priority that matters above everything else. Tatum spent 298 days recovering from his Achilles rupture before returning this season , and his left knee is now a concern. The Celtics need to invest the entire summer into his recovery, his workload management plan, and his long-term durability. Without a healthy Tatum, nothing else matters.

2. Find a third scoring option. Tatum and Brown are a legitimate top-2 duo. But when either one of them goes down, Boston has no one capable of creating consistent offence against a playoff defence. They need a third scorer — someone who can put the ball on the floor, draw fouls, and get buckets in the fourth quarter. That player needs to be acquired this summer, whether by trade or free agency.

3. Address the three-point shooting reliability. The Celtics are a great shooting team — until they’re not. Their all-or-nothing dependence on the three-pointer is a playoff vulnerability that good coaches exploit. They need to develop more mid-range creation and paint attacks so they have a secondary offence when the threes aren’t going in.

4. Evaluate Jaylen Brown’s role. Brown has been a loyal, productive Celtic for nearly a decade. But at $304 million over five years, he is one of the highest-paid players in the NBA — and his performance in the biggest moments of this postseason raised real questions. The Celtics need to have an honest internal conversation about whether Brown is the right co-star for Tatum, or whether a trade that brings in a different piece could elevate this team to another level.

5. Culture and communication. Payton Pritchard’s pre-Game 7 comments were damaging and unnecessary. Championship teams have a discipline and a professionalism about what they say publicly. Boston needs to reinforce that culture internally — because one careless comment from a bench player directly motivated the opposing superstar in a Game 7. That cannot happen again.

Bottom Line

The Celtics’ 2025-26 season ends in the first round. It’s a brutal result for a team that spent most of the year as a legitimate contender — and it was delivered in the cruelest possible way, with their franchise player sitting in street clothes in the biggest game of the year.

But context matters. Tatum missed most of the regular season. Boston still finished second in the East. They built a 3-1 series lead. They were competitive until their best player’s body failed them. This is not a rebuild. This is not a crisis. This is a team that needs one healthy season from Jayson Tatum — and when that happens, the Eastern Conference had better be ready. 🏀