LeBron James had 27 points, 10 rebounds and eight assists and Kyrie Irving added 24 points, but the big story was the injury to Kevin Love. He left the game in the first quarter with a left shoulder injury and didn't return. It was a bizarre game full of injuries and scuffles.
It was a physical game throughout, but the Cavaliers dominated all afternoon. They led 57-36 at the half. The Celtics cut the lead to single digits in the third quarter, but Cleveland was too good. They maintained their lead in the fourth to hold on for a win despite a furious rally from the Celtics in the game's final minute.
It's the first playoff series win for the Cavaliers since James' last trip to the playoffs in a Cleveland jersey in 2010. They'll face the winner of the series between the Chicago Bulls and the Milwaukee Bucks -- the Bulls currently lead 3-1.
Here's three things we learned Sunday.
1. The Cavaliers are the team to beat in the East
Sunday's win wasn't some amazing display of skill, but in the Eastern Conference, it's good enough. The Cavaliers have been on fire since James' midseason sabbatical, while the rest of the East has sputtered. The top-seeded Atlanta Hawks are struggling to score against the Brooklyn Nets, so the toughest series for the Cavaliers may come in the next round when they face the Bulls.
Love's status certainly affects their NBA title hopes, but the Cavaliers have the advantage of being able to fight through the East while giving Love time to recover.
This team has been all about James and Irving. Love will be missed, but he's not the go-to guy. As long as James and Irving are playing at the level they're capable of, they're going to be tough to beat with or without Love.
2. The Cavaliers showed they want to be tough, but they should have backed off
When Love injured his left shoulder after getting tangled with Kelly Olynyk in the first quarter, his teammates weren't pleased. First, Kendrick Perkins set a hard screen on Jae Crowder.
But that wasn't it. In the third quarter, J.R. Smith backhanded Crowder under the hoop and Crowder sprained his left knee.
It was a foolish play, Smith was ejected and could definitely get suspended for the first game of the second round. The Cavaliers had nothing to gain by knocking Crowder out of this game. It's understandable to want to stand up for your teammate, but you're more useful to the team on the court than off it.
3. The Celtics are fighters, but just aren't that good
The Boston Celtics and coach Brad Stevens deserve all the credit in the world for getting this team to the playoffs, but in the Eastern Conference, it's not nearly as impressive. They played tough, inspired basketball all season long, but they didn't have the talent to match up with Cleveland. After the sweep, the Celtics ended the regular season and postseason with a combined record of 40-46. The future is bright with players like Marcus Smart and the energetic Isaiah Thomas, but the Celtics have a ways to go.