Irving shot several clutch three-pointers in the 117-108 win, which saw the Celtics strengthen their playoff place.
The Celtics, who move to 26-18, have been disappointing so far this season.
Before the year began, they were tipped to at least make it to the NBA Finals, but have struggled to click as a team.
In their last ten games, the Celtics have won six and lost four, and will hope that the win over the Raptors will help catapult their season.
Before the game at the TD Garden, the Raptors were top of the NBA Eastern Conference, but following this loss they have dropped to second place behind the Milwaukee Bucks.
Earlier in the week, Irving blasted his team-mates for not knowing what it’s like to win a championship.
The Celtics’ #11 was part of the 2016 Cleveland Cavaliers that came from 3-1 down to win the NBA title against the Golden State Warriors, and Irving believes the team has to do more.
And speaking after the Raptors win, the guard sent out a warning shot to the rest of the league.
“What’s the NBA without a little drama?” he said.
“For us, it’s literally about growing, that’s all.
“We’re trying as a group.
“We’re trying as individuals.
“We’ve got to come together at times like this
“It’s great to see we can still smile, still compete at a very high level against the best.
“We’ve just got to become more consistent, and once that happens we’ll run over everybody in this league.
“I guarantee that.”