Grant Williams leads Boston Celtics past Milwaukee Bucks in convincing Game 7 victory 6:25 PM ET Andrew LopezESPN BOSTON -- For the fourth time in the last six seasons, the Boston Celtics are headed to the Eastern Conference Finals. The hope is this time, they can take it one step further. To do that, they'll have to do exactly what the TD Garden crowd started chanting late in the fourth quarter: "Beat the Heat." Grant Williams had a career-high 27 points, Jayson Tatum had 23 points and the Celtics hit a playoff franchise-record 22 3-pointers as the Celtics defeated the Milwaukee Bucks , 109-81, in Game 7 at the TD Garden on Sunday afternoon. In the previous three Eastern Conference Finals, the Celtics have come up short. But after getting through the defending champions on Sunday, there's hope this year could mark the storied franchise's first trip to the NBA Finals since 2010. But in order to get there, they'll have to go through the top-seeded Miami Heat . That best-of-seven series starts on Tuesday in Miami. Williams had never attempted more than eight 3-pointers in a game before this series. He was 6-of-9 from deep in Game 2 but blew those attempts out of the water in Game 7 in record fashion. Editor's Picks Bucks cancel Game 7 watch party after shootings 23h ESPN News Services 2 Related His 18 attempts are the most ever attempted in a Game 7 in NBA history. It also ties Ray Allen for the most three-point attempts ever by a Celtics player -- and that was a triple overtime game against the Bulls in 2009. His seven makes ties him with Stephen Curry (twice) and Marcus Morris for the most 3-pointers ever in a Game 7. Williams didn't enter the NBA as a three-point shooter. In fact, he made only 15 threes during his final season at Tennessee and only 30 in his career as a Volunteer. He shot 25% as a rookie from three but improved that to 37.2% last season. This year, he upped both his volume and his percentage as he nailed 41.1% while shooting 3.4 a game. But against the Bucks, Williams had struggled since his Game 2 performance going just 2-of-14 from deep in his last four games. Because of that, Milwaukee decided to leave Williams open for most of the game. He responded by hitting the first shot he took, a three from the left wing. From there, he continued to fire away. Boston finished the game shooting 22-of-54 from three-point range while the Bucks struggled mightily going just 4-of-32. According to ESPN Stats and Information research, that's the largest 3-point differential in a Game 7 in NBA history and tied for the largest 3-point differential in any playoff game (Golden State had 21 to Oklahoma City's 3 in Game 6 of the 2016 Western Conference Finals). The Eastern Conference Finals start on Tuesday night in Miami.