WATCH: Marcus Smart is a split-second late on game-winning buzzer-beater as Celtics fall to 76ers in Game 4

The Boston Celtics and Philadelphia 76ers just delivered an all-time classic in Game 4 of their second-round series. Plenty of games come down to the final seconds, but this one came down to the final fractions of a second.

The decisive sequence took place with less than one minute remaining. Jayson Tatum got away with a blatant push-off to put the Celtics ahead, 115-113, with 38 seconds remaining. Philadelphia responded by working the ball into Joel Embiid inside, and when the double arrived, he hit James Harden in the corner for a 3-pointer that put Philadelphia ahead, 116-115.

At this point, many coaches would have chosen to call a timeout to draw something up. Joe Mazzulla elected not to, and the Celtics played on and eventually created an open 3-pointer for Marcus Smart. It swished… but just barely came after the final buzzer had sounded. The shot didn’t count. Philadelphia won.

The decision not to call a timeout at any point in that final possession will likely haunt the Celtics, but it made sense in context. Boston got up a clean look at the end of regulation largely because Philadelphia wasn’t able to sub Tyrese Maxey out of the game. Tatum hunted him and used that matchup to create a wide-open 3 for Smart, who simply missed it. Mazzulla has avoided calling timeouts in these situations for most of the year. It just came back to haunt him in Game 4.

Now Philadelphia has evened its series with Boston at two games apiece. Harden has two 40-point masterpieces, Embiid is starting to look healthier, and the 76ers have all of the momentum. Boston had a chance to effectively seal the series on Sunday. Instead they were less than one second late. Now we’re tied with three games to play.