Watch: Payton Pritchard's miracle three caps Celtics' first-half run

Per ESPN's Malika Andrews, the 49-foot make was the longest shot in the finals in the last 25 years.

The buzzer-beater was Pritchard's second of the NBA Finals, too. He notched one at the end of the third quarter of Game 2, which gave the Celtics a nine-point lead, 83-74, in an eventual 105-98 win.

"I probably blacked out a little bit," he said about his make earlier in the series. He might have lost consciousness again on Monday. 

The Game 5 shot was a microcosm of a first half in which the Celtics could do no wrong.

Boston built a 21-point lead, 67-46, while shooting 52.1 percent, including 47.6 percent (10-of-21) from beyond the arc.

The Celtics were led by forwards Jaylen Brown and Jayson Tatum, who combined for 31 points. However, the first-half blowout was due to an all-around team effort. 

Boston is 24 minutes away from a record 18th NBA championship. With Pritchard's miracle shot falling, it's starting to look like it will be the Celtics' night.