Grant Williams was the unexpected hero as Boston Celtics defeated Giannis and the Milwaukee Bucks to advance to the NBA Eastern Conference Finals.

Williams scored a career-high 27 points and hit seven 3-pointers while Jayson Tatum added 23 as Boston set a Game 7 record with 22 3-pointers to eliminate the NBA champions 109-81.

The Celtics trailed early in Game 7 before outscoring the Bucks 61-38 in the second half to cruise to the victory.

Bucks meanwhile finally felt the absence of Khris Middleton as they went 4 for 33 (12.1%) from the 3-point line. The second-worst 3-point percentage in a playoff game ever (minimum 30 attempts).

Williams was timid early, missing 5 of his first 7 3-point attempts before settling in and finishing 7 for 18 behind the arc.

It helped silence another relentless night from Bucks star Giannis Antetokounmpo, who had 25 points, 20 rebounds, and nine assists.

He became the only player in history to score 200 points, 100 rebounds, and 50 assists in a single series but it was not enough.

Giannis was just 3 of 11 in the paint in the second half, including 1 for 6 in the fourth quarter.

Jrue Holiday added 21 points and eight assists while Brook Lopez finished with 15 points and 10 rebounds.

Boston started the second half on an 11-4 run to open a 59-47 lead.

Even with Tatum sitting with foul trouble, the Celtics outscored the Bucks 16-11 to take a 79-64 lead to the fourth before finishing things off.

Boston Celtics in the Eastern Conference Final will face the top-seeded Miami Heat in a rematch of the 2020 finals which the Heat won in six games.