Horford's three blocks were part of a monster effort that buoyed his double-double that came with 20 points and 11 rebounds.
Jaylen Brown chipped in with 19 points and Gordon Hayward had 13 off the bench for the Celtics.
As the first team to advance to the second round, the Celtics had plenty of time to rest and prepare for the No. 1 seed Milwaukee Bucks.
On the other hand, the Celtics trio of Al Horford, Kyrie Irving, and Jaylen Brown accounted for 65 points, 22 rebounds, and 14 assists on 55 percent shooting from the field.
The upcoming game will be a chance for the Bucks to rebound, but to do so, they will have to figure out a way to allow Giannis to play to his fullest potential.
Raptors carry edge heading into Game 1 against 76ers
Then there's James Ennis behind Jimmy Butler and Jonathon Simmons behind Tobias Harris and at the guard position you have T.J. But the 76ers have dropped 13 straight games at Scotiabank Arena - their last road win in Toronto came in November 2012.
"It just seemed like Milwaukee was a way better team throughout the regular season, but when I watched this today, if Giannis doesn't have a monster game, and somebody else besides him doesn't step up, Boston is just going to out-talent them".
"Kyrie doesn't need to perform perfectly every night, which may give us an advantage", he said.
Milwaukee's best stretch of the game came just past the midpoint of the second quarter, after it had fallen behind 40-25. They would finish up the first quarter down 26-17 with not a lot of answers on the offensive end.
The Celtics led by as many as 15 points in the first half before the Bucks went on a run before halftime. The home team regained momentum in the second quarter and pulled with 52-50 at halftime. Is he the guy who's going to get you a bucket with the game on the line, a playoff game or a playoff series on the line?
"It's a great start to a series", Irving said.