BOSTON – One thing became abundantly clear Sunday afternoon at TD Garden: these Boston Celtics are not the Toronto Raptors.

They aren’t the 2017 Celtics or the 2015 Celtics, either.

Those teams are and were incapable of providing any resistance to LeBron James and the Cleveland Cavaliers. This Celtics team is different. This Celtics team is confident.

Game 1 was proof that this Boston team is not only capable of providing resistance; it is actually capable of delivering utter domination.

As James admitted following Sunday’s matchup, Boston made its presence felt from the opening tip. It took only three seconds for the C’s to score, and the next 47 minutes came up green as Boston logged a blowout win, 108-83.

“(Al) Horford tipped it right to Jaylen Brown and it looked like we had two on him, and next thing you know he's getting a layup right off the tip,” said James, who scored just 15 points while committing a game-high seven turnovers. “So that kind of set the tone right there.”

By the middle of the first quarter, few were wondering if the Celtics would be able to win Game 1. The real question was, by how much?

The Celtics went on to pull ahead by as many as 29 points during their victory, dominating nearly every facet of the game en route. Boston shot better, it passed better, it rebounded better, and it defended better. Most notably, it managed to contain James, who entered the series riding quite possibly the best stretch of basketball of his Hall of Fame career.

“I just thought our guys were locked in,” Brad Stevens said of his team.

The same could not be said of the Raptors, who were swept away with ease by the Cavs just a week ago. Toronto, which was the top seed in the East, had no answers for James or for any of his teammates. Cleveland ran Toronto out of the gym, and at times, it appeared as if the Cavs owned real estate inside the Raptors’ minds.

Truthfully, the same could be said of the last two Celtics teams which faced James and the Cavs during the postseason. Cleveland swept the C’s out of the 2015 Playoffs, and then ousted Boston 4-1 during last year’s Conference Finals. Boston was fortunate to win even one of those nine games, as it somehow rallied from 21 points down to snag the win on the road.

Al Horford, who scored 20 points Sunday afternoon and was a member of last year’s Celtics team, admitted after Sunday’s Game 1 that his team stood on much shakier ground as it entered last year’s series against Cleveland.

“I normally don't like comparing teams,” Horford said, “but last year we came off of a grueling seven-game series against Washington, one day rest, and we had to play Cleveland.”

This year was a whole different story. Boston took care of business Wednesday night during Game 5 against Philadelphia, and that victory provided the team with three days off before Sunday’s Game 1. That gap of non-game days allowed the players to recuperate, the coaches to craft a masterful game plan, and, potentially most importantly, for the team to build an understanding and belief that they truly can win this series.

Boston entered Eastern Finals with budding confidence, and it showed during Game 1. The Celtics out-played, out-executed and out-hustled Cleveland from start to finish. They provided more than just resistance. They thumped their visitors, and that’s a far cry from what the Raptors or recent Celtics teams were able to bring to the table against the Cavaliers.

Leading up to Game 1, there was a different aura around Boston. Now, as we move to Game 2, there’s a different aura around the series itself. The C’s showed the world that they’re here because they belong.