The first six weeks of the NBA season have been a celebration of Kyrie Irving, who has stepped to center stage with the Boston Celtics and led them to a breathtaking 18-3 record, including a handful of remarkable fourth-quarter comebacks.

Fully on display now that he's away from LeBron James, Irving's existing talents of clutch playmaking and isolation wizardry have captured attention.

The key, though, seems to be turning both ways. Irving has clearly been unlocked to a degree, especially late in games. But so has James, and the results are equally extraordinary, if not as attention-grabbing as more focus was aimed toward the Cleveland Cavaliers' rocky start.

Like Irving, James is in the midst of some of the finest clutch play of his career.

In clutch time -- defined as the last five minutes of a game when the score is within five points -- Irving leads the league with 65 points thus far. James is second with 60. Field goal percentage in those situations? James is first leaguewide at 62.2 percent; Irving is second at 61.5.

James is first in the league in fourth-quarter scoring, putting up 168 points and averaging 9.3 per game. Irving is fourth in fourth-quarter scoring with 125 total points.

Clutch Time This Season* Irving James Points 65 (1st in NBA) 60 (2nd in NBA) PPG 5.4 (2nd) 5.5 (1st) FG% 61.5 (2nd) 62.2 (1st) +/- +29 (T-5th) +26 (11th) * last five minutes with

score within five points

Clutch Time Last Season* Irving James Points 110 (21st in NBA) 112 (20th in NBA) PPG 3.5 (15th) 3.2 (22nd) FG% 40% (30th) 53% (2nd) +/- +45 (T-29th) +54 (19th) * min 50 field goal attempts

Last season, James and Irving ranked 20th and 21st, respectively, in total clutch scoring, per ESPN Stats & Information. Breaking them apart has allowed each to shine.

"The last couple years, Kyrie obviously being as great as he was in the fourth quarter, we kind of pick our games. There was games half the time that he had it going and, 'Hey, go get it.' There was games half the time where I had it going, and I'd go get it," James said.

"Right now my teammates look at me and they're like, 'OK, like, this is your quarter, you've done this your whole career. Let's try to make some things happen.' It's very important that I try to come through for them."

Even outside of so-called crunch time, James' fourth-quarter dominance is striking. He's first in fourth-quarter assists, points in the paint and even blocks. He has the best fourth-quarter field goal percentage at 57 percent -- Irving is tied for 12th at 50 percent -- and James is in the top 10 for fourth-quarter 3-point percentage at 39 percent.

"We couldn't find a solution to stop him in the fourth quarter," Brooklyn Nets coach Kenny Atkinson said after James dropped 23 points on his team in the frame last week. "We were trying different stuff. I guess we could have trapped him, but he's such a great passer; we didn't want to give up 3s. You've got to give him a lot of credit."

It's part of what has been a tremendous start to the season for James, who is playing some of the best regular-season basketball since he returned to Cleveland. It has been highlighted by improved shooting, leading him to becoming the most efficient player in the NBA to this point.

LeBron James has raced out to an NBA-leading 30.56 player efficiency rating this season. Ken Blaze-USA TODAY Sports

James is shooting 58 percent overall and 42 percent on 3-pointers. It's early, but those would be the best marks of his career. He even has improved his free throw shooting from 67 percent, which was a career worst last season, to 77 percent, which would be his best mark in five years.

"My man has worked his way into being a real shooter. Like, for real. He can really shoot," teammate Kyle Korver said of James. "His fundamentals, he has worked on it, in this last year that I've been here. His shot is really, really good. He's worked hard, and it's showing."

James told ESPN's Dave McMenamin earlier this season that he adjusted his shooting stroke in the offseason to deal with some elbow soreness. It seems to be having a positive effect. In addition to his improved 3-point and free throw shooting, James has boosted his midrange shooting dramatically. Last season he was at 31 percent on shots from 16 to 24 feet. This season that number has gone to 43 percent.

"Hopefully at this point in my career I know my shot more than anybody," James said. "I've played with Mike Miller and Ray Allen and James Jones and Kyle Korver, Rashard Lewis is on that list, I've played with some of the greatest 3-point shooters -- and hopefully I'm not forgetting any of 'em -- that's ever shot the 3-ball. I've been around and I've listened and studied the way they shoot the ball and their preparation and things of that nature. They all have had some input."

All of it is happening as James is playing all over the floor. Because of injuries to Tristan Thompson, Derrick Rose, Iman Shumpert and Isaiah Thomas, James routinely plays center defensively and point guard offensively late in games.

"My man has worked his way into being a real shooter. Like, for real. He can really shoot."

During the Cavs' seven-game win streak, he has been tasked with shutting down the likes of Kristaps Porzingis and Blake Griffin for periods in the fourth quarter as well as defending guards like Kemba Walker, which he did on the final possession of the Cavs' win over the Charlotte Hornets on Friday night.

During his time in Miami, coach Erik Spoelstra nicknamed James "1 through 5" for his ability to play any position at any time. But even by the standards Spoelstra held him to, James' positional flexibility recently has been impressive.

LeBron Shooting Distance

This Season vs. Last Season 2017-18 2016-17 Midrange 42.9 36.2 16-24 feet 42.5 30.7 24+ feet 42.2 36.5

It has all added up to a player efficiency rating of 30.56, which is currently best in the NBA. James used to own this category, as he was the league's PER leader for six straight seasons from 2007-08 to 2012-13. The four times in his career when he has crested the 30 mark, he has won the MVP award.

The highest he has been since returning to Cleveland was 27.5, during the Cavs' championship season in 2015-16. But the past three years he has been sharing with Irving. Now that his former teammate is in Boston, the best of James seems to be coming out again.

"I put a lot of work into my craft," James said. "I believe that every shot I take is going to go in."