The Boston Celtics stormed back in Game 4 to force overtime against the Philadelphia 76ers. Yet, once again they came up short in the final seconds, losing 116-115.

The Celtics had a 115-113 lead before former MVP James Harden cashed a clutch 3-pointer for the Sixers. Boston responded with a triple of its own, however, it was about a split second late, sealing Philly's victory.

The Sixers and Celtics are all tied up with the series at 2-2. Before we look ahead, let's discuss the three Celtics who shoulder the most blame for the Game 4 defeat.

3. Jaylen Brown

Celtics star Jaylen Brown played a solid game all things considered. He was red hot in the first quarter and finished with 23 points, five assists, and just one turnover. Yet, he's on this list mostly because of Philly's final play.

Sixers center Joel Embiid was going at Celtics forward Jayson Tatum with less than 30 seconds to go. While Embiid could've ended up scoring on Tatum in the paint, the most he could've done at that point was tie the game up with a two-pointer. But once Brown ran at Embiid to provide help defense, Harden was left alone in the corner for the dagger.

If Brown stays on Harden, Embiid probably couldn't have swung that pass to the perimeter. Brown abandoning his post while the C's were up two ultimately led to the game-changing shot.

2. Marcus Smart

Prior to Brown's blunder, the C's had another chance to win the game, this time in regulation.

Tatum found Celtics point guard Marcus Smart for a wide-open triple, but he couldn't convert as time expired:

Live and breathe the NBA?

🚨 Get viral NBA graphics, memes, rumors and trending news delivered right to your inbox with the Clutch Newsletter.

The Celtics went 17-of-44 from beyond the arc and missed a lot of great looks. Smart's was particularly brutal, as that final shot would've prevented the overtime heartbreak. Speaking of overtime, Smart almost made up for his miss in the fourth quarter, yet his potential game-winning shot was just a little too late:

But, as much as one can blame Brown and Smart, they willed the Celtics back into the contest. Brown led the charge in the first half and Smart made pivotal defensive plays to keep the C's alive:

Overall, most of the blame for the Game 4 loss could arguably be pinned on someone who wasn't even on the court.

1. Joe Mazzulla

The Celtics' first-year coach has likely exceeded expectations this season, yet his decision-making late in Game 4 was a bit puzzling.

Following Harden's 3-pointer with 19 seconds left in overtime, the Philly crowd was rocking. And although the Celtics still had a chance to win, Mazzulla elected to not call a timeout and let it play out.

The Celtics ended up running out of time in the final seconds, raising a major question: why didn't Mazzulla call a timeout?

He had two to spare and could've set up a play for Tatum or Brown with a fair amount of time on the clock. Instead, the C's looked a little discombobulated and missed a prime opportunity to go up 3-1 in the series.

Mazzulla also chose not to call a timeout prior to Boston's final shot attempt in the fourth quarter. The 34-year-old coach has had an aversion to timeouts this season, as he believes that sometimes letting his team figure it out themselves is the best option.

That gamble didn't work in Game 4, which means the C's have to go back home with the series tied. If the Celtics want to advance, they'll need to come out firing and with much better decision-making–especially late in the game.