Grant Williams exploded for a career-high 27 points and led a defensive charge on Milwaukee star Giannis Antetokounmpo as the host Boston Celtics advanced to the NBA's final four with a 109-81 romp over the defending-champion Bucks in Game 7 of their Eastern Conference semifinal series on Sunday afternoon.

Jayson Tatum chipped in with 23 points and Jaylen Brown 19 for the second-seeded Celtics, who will advance to face the top-seeded Miami Heat in the Eastern Finals. Game 1 is scheduled for Tuesday in Miami.

The Celtics will be making their fourth trip to the Eastern Finals in the last six seasons. They have not advanced to an NBA Finals since 2010, having lost four consecutive times when one step away, twice to the Heat and twice to the Cleveland Cavaliers.

After losing twice at home earlier in the series and falling behind 10-3 in the best-of-seven finale, the Celtics dominated the final 44 minutes, especially from long range.

Williams, a third-year pro who had never scored more than 21 points in his NBA career and never made more than six 3-pointers, stunned the Bucks with 7-for-18 accuracy from beyond the arc, accounting for all but six of his points.

"I told him to ‘Let it fly. They're disrespecting you more tonight than earlier in the series,'" Celtics coach Ime Udoka said of his message to Williams. "That was the plan for him and other guys."

Tatum added five 3-pointers and Payton Pritchard four as the Celtics shot 22-for-55 on 3-point tries, outscoring the Bucks by a whopping 66-12 from beyond the arc.

With Jrue Holiday and Pat Connaughton combining for 0-for-11, Milwaukee went just 4-for-33 from deep.

After a last-second foul on Antetokounmpo on a Marcus Smart 3-point heave from beyond half court had helped the Celtics build a 48-43 halftime lead, the hosts gradually pulled away throughout the second half.

Williams, Tatum and Brown all hit 3-pointers in an early burst in the third period that opened a 59-47 lead, and Milwaukee was never closer than 10 after that.

"They were the better team in a seven-game series," Bucks coach Mike Budenholzer said of Boston.

Pritchard finished with 14 points and Smart 11 for the Celtics, who stayed alive with a 108-95 win at Milwaukee in Game 6 on Friday.

Smart completed a double-double with a game-high 10 assists, while Al Horford was the Celtics' top rebounder with 10 to go with six points and six assists.

Antetokounmpo, who had averaged 35.3 points on 46.8-percent shooting in the first six games of the series, was harassed into 10-for-26 shooting and limited to a team-high 25 points.

"I felt like we started grinding him down," Udoka said of the two-time league MVP. "He missed some of the easier shots around the basket. That's what we talked about. It's not just one guy (guarding him). We stuck with that."

Antetokounmpo also found time for a game-high 20 rebounds and team-high nine assists.

Holiday finished with 21 points and Bobby Portis 10 for the Bucks, while Brook Lopez logged a double-double with 15 points and 10 rebounds.

The Bucks played the series without three-time All-Star Khris Middleton, who sprained the MCL in his left knee during Game 2 of the first-round series against the Chicago Bulls.

"Every team goes through something. Nobody feels sorry for us," Budenholzer said. "It's the age-old equation: You've got to have good players; you've got to be a little lucky; and you've got to be healthy. You need all of these things to be successful in the playoffs. I've heard it a million times. We weren't as healthy as we could have been, but nobody cares."

--Field Level Media