Jimmy Butler made two free throws with no time remaining after controversial foul calls at the end of game.
The Celtics have put a major emphasis on making Toronto uncomfortable beyond the arc, and it is working.
Smart scored 19 points and was a big key in the Game 2 win.
The Celtics needed a spark in the fourth quarter, and Smart launched a barrage of 3-pointers that changed the game.
The Nuggets became the 12th team in NBA history to overcome a 3-1 deficit to win a series.
Jayson Tatum scored a career playoff-high 34 points for Boston.
It felt like a transformative week in sports, one that showed why athletes should never stay out of politics.
Hayward was expected to be out four weeks when he sprained his ankle, and two weeks have passed.