INDEPENDENCE, Ohio -- LeBron James said the Cavaliers are "sharp in the mind" as they head into this first-round series with the Indiana Pacers on Sunday.

Sounds simple, but, more or less, it's how James says he's won 21 straight games in the first round, has never lost an opening series, and has never lost the first game in any playoffs over 12 seasons.

The 21 in a row is an NBA record for first-round series.

"We do a great job of getting prepared," James said. "And every team I've been on has always been prepared going into the first round of the postseason and I feel like we're well prepared again."

The Cavaliers swept the Pacers out of the first round last year, though both teams are markedly different. In Cleveland's case, James still has Kevin Love but no Kyrie Irving and a bunch of new role players.

With the Pacers, Paul George is out and Victor Oladipo runs the show, along with newcomer Darren Collison.

But James' Cavs swept the Pistons in the 2016 playoffs opener, and the Celtics in 2015. His Heat wiped out the Hornets in four and the Bucks in four the year before that. A James team hasn't lost a first-round game since May 6, 2012, when the Heat lost Game 4 to the Knicks by two points.

The names, the teams, the opponents, the teammates -- they all change. The constant, dominant force remains James.

"My responsibility has been the same for quite a while now: Go out and try to dominate," James said.

James is averaging 29 points, 8.8 rebounds, and 6.9 assists in 55 career first-round games. He's won 48 of them. In last season's sweep of the Pacers, he was just ridiculous. James became the first player in NBA history to average at least 32 points, nine rebounds, nine assists, three steals and two blocks in a playoff series.

At 33, James is also coming off arguably his finest regular season. He played in all 82 games for the first time and led the league in total points, finishing the year with averages of 27.5 points, 8.6 rebounds and 9.1 assists. James posted career highs in triple doubles (18) and double doubles (52).

"LeBron is a freak of his own," Oladipo said this week. "He's the best player in the world. You could give it (the MVP Award) to him every year but it wouldn't be fair to everyone else."

In a way, all of this first-round dominance makes sense. James' teams have gone to the last seven Finals, so it would stand to reason that in each of the last seven years his first-round opponent was overmatched.

"He definitely understands that, going to The Finals, that the quicker you can get a series over and get some rest is the best way to do it," Pacers coach Nate McMillan said. "So our guys have to understand that we're gong to see the best (team) at their best."

The Pacers, though, represent the best chance to snap the streak of consecutive first-round wins.

As for upsetting the Cavs and knocking them out in the opening round...let's not get carried away. But the Cavs, as the No. 4 seed -- the lowest James has had going into the playoffs in at least a decade -- were only a game ahead of the No. 5 Pacers in the East.

"I don't have any concerns," James said. "Listen, it's going to be a very good matchup. It's 4-5 for a reason. Both teams played good ball at times throughout the regular season. Obviously their season, from the outside looking in was more productive than ours because of what they went through in the offseason. But we went through a lot in the offseason as well. It's a good matchup and we look forward to the challenge."