The Golden State Warriors were up 87-72 in the third quarter, on their home floor, with Stephen Curry playing at his peak. It looked like the Dubs would cruise to victory and add to a 21-2 Game 1 record under Steve Kerr.
Not so fast.
Trailing by 12 entering the final frame, the Celtics started hitting shot after shot before mounting a 40-16 fourth quarter, which included a 20-2 run, to complete the most lopsided quarter in NBA history and steal Game 1 on the road.
And best of all? This wasn't Jayson Tatum and Jaylen Brown leading the comeback, this was 36-year-old Al Horford, new father Derrick White and pesky Marcus Smart.
Amazed by the potentially series-altering comeback, players, fans and media shared their reactions on Twitter: