5 reasons why the Knicks upset the Celtics

The New York Knicks ended the Boston Celtics' championship repeating aspirations in six games in the Eastern Conference Semifinals. With that, a lot went wrong for Boston, while a lot went right for the Knicks.

Going into the offseason, there will be plenty of questions about what's next for Boston, but for now let's look back at how the Knicks did the near-impossible to send the Celtics packing. Here are five reasons why the Knicks upset the Celtics:

After Game 5's loss at TD Garden, the Knicks came back to New York and showed the league they still meant business. Setting their defense aside - more on that later - the Knicks took advantage offensively at the right times during the series. Game 6 they jumped out to an early lead - helped by the Celtics apparent inability to hit their shots - and were able to coast to an as much as a 41-point lead.

Friday was slightly off the norm for the series because the Knicks dominated the entire game, as opposed to the climbing back from a late-game deficit. In the end, New York shot 42-for-91 (46.2 percent) from the floor and 16-for-45 (35.6 percent) from three. But, their early onslaught seemingly put the Celtics out of reach.

In the strategic battle between coaches Tom Thibodeau certainly outdid Celtics coach Joe Mazzulla. For game-to-game adjustments and in-game switches, Mazzulla was outmatched. Prime examples being, of course, the three, the 'hack-a-Mitch' tactic of intentionally fouling Mitchell Robinson, and even something like Luke Kornet predictably regressing in Game 6 after a big Game 5.

All in all, Mazzulla showed some flaws in the series. He needs to make in-game adjustments quicker and more decisively. His lack of adjustments could be worrisome in the future unless addressed.

Following an opening playoff series with the Miami Magic where the Celtics utilized a more diverse and creative brand of basketball, the Celtics attempted to make the Knicks series a make-miss affair. It was clear from Game 1 - where they shot 15-of-60 from beyond the arc - that the Celtics would be content just firing away threes at will, regardless if they were falling or not.

In the end, this did not work out for them, as they found themselves shooting their way out of contention. Mind you, it wasn't that the Celtics shot an exorbitant amount more threes than the Knicks in the series (Celtics: 217 attempts, Knicks: 202 attempts), nor was their 3-point shooting percentage worse -- in fact, it was better (Celtics: 37.8 percent from three in the series, Knicks: 35.1 percent). What got Boston in trouble was the incredibly inopportune times they elected to shoot the doors off and miss, coupled with their unwillingness to try anything else - for the most part.

The prime examples of this are the two 20-point blown leads from Games 1 & 2, when the Celtics sat back and just fired away from deep allowing New York to crawl back. Even in Game 6 the Celtics shot themselves in the foot from three (no pun intended) by just firing away from outside the arc with no apparent rhyme or reason - Derrick White was culpable for this, shooting 2-of-8 from three.

The phrase: 'The Celtics live and die by the three,' has been reiterated over-and-over again for nearly the entire season. At the end of the day, the season was ended because of the three. For those who remember, the Celtics had a month and a half stretch from December-through-February where they played .500 basketball because they couldn't nail the three efficiently.

Even back then there were calls for a system change, they did not. In fact, the thing that changed was they hit their threes for a time. However, all water finds its level, and that's how the Celtics found their way out of the 2024-25 race.

The Celtics and their high-powered, run-and-gun offense was shockingly stymied by the New York defense - a team that had not been known for their defensive prowess. It was Mikal Bridges who stunned the Celtics in the end of Games 1 & 2, also contributing six combined steals during the first two in Boston (he finished the series with a whopping 14 steals). Plus, the Knicks' strong defense was also aided by the Celtics' inability to hit shots for most of the series.

But the Knicks' defense playing above its head was, as aforementioned, enhanced by the Celtics' stubbornness offensively. There were countless examples during the series when the Celtics would have five outside and the Knicks playing man-on-man defense with nobody inside, essentially shutting off the outside threat. But, even with nobody in the paint, the Celtics still chucked it up from deep.

To quantify how strong the Knicks' defense was during the series, the numbers show that the Celtics scored 11 fewer points per game in the Eastern Conference Semifinals. Boston averaged 105.2 points per game against the Knicks as opposed their regular season average of 116.3 points per game. Excluding Game 5, when the Celtics scored 127 in a do-or-die situation, they averaged just 100.8 points the rest of the series.

The more 'unsung' area where the Knicks bested the Celtics is with the consistent contributions they received from their support players. The battle of secondary scoring went decidedly to the Knicks, who got a major boost from a few key players.

The defensive help that Mikal Bridges gave New York has already been discussed, but he also helped out offensively, adding 14.7 points per game plus a 23-point performance in Game 4. OG Anunoby got his scoring in spurts, but still contributed 85 total points (14.2 per game). His largest performance was in Game 1 where he registered 29 points. Also, the most quiet contributor of the series for the Knicks was Josh Hart. Despite getting very little recognition all series, Hart brought it for most of the series with 14.5 points per game and a Knick leading 24-point Game 5.

Conversely, the Celtics secondary scorers, and some of their stars, underwhelmed for most of the series. Kristaps Porziņģis, who continues to battle an undisclosed illness, averaged just 5.6 points per game and only reached double-digit scoring in Game 5.

However, the lack of scoring goes beyond Porziņģis, as Payton Pritchard (14.2 points per game), Jrue Holiday (9.3 points per game), and even Derrick White (19.3 points per game, 16.3 not including Game 5's 34-point performance) underwhelmed for much of the series.

So, what can be taken from the Knicks series is the Celtics cannot survive in the long-run when only relying on their stars. Obviously, nobody expected the support players to be the difference - and to be fair it may not have been, the Knicks stars were very important - but it undoubtedly played a major role.

Now, the Knicks advance to the Eastern Conference Finals, and Celtics fans are left wondering what their team will be next year. With Jayson Tatum recovering from Achilles Tendon surgery, Jaylen Brown potentially needing surgery as well, and the inevitable roster deconstruction on the way, the 2025-26 Celtics may look very different. But inspire of the changes to come, what can be said is the Celtics had a lot of mistakes that guided them to an early summer.

Luke Graham is a digital sports content co-op for 98.5 the Sports Hub. He is currently a sophomore at Northeastern University studying communications and media studies. Read all his articles here, and follow him on X @LukeGraham05.