James, a 15-time all star, finished with a season high 39 points and added 16 assists and 12 rebounds for the Lakers.
"After the injury last year I wasn't myself," said James. "I heard it all. I heard it all from my year 17. Is this the last we seen of LeBron? He's not very good at defence."
James stepped up his game in the overtime session, drawing a foul on a layup for a three point play that gave Los Angeles a 110-103 lead.
James said teams make the mistake of underestimating his defensive skills.
"You can't single me out on defence because I am in tune with that side as well. It is important for me," he said.
James wasn't the only player to register a triple double. Mavericks star Luka Doncic finished with 31 points, 15 assists and 13 rebounds for his 10th career triple double. At 20 he has the most triple doubles in history for a player under the age of 21.
Anthony Davis delivered 31 points and eight rebounds in the win. Lakers reserve Dwight Howard was involved in two controversial plays near the end of the game that could have resulted in calls against the Lakers at key moments but didn't.
Howard clashed heads with an unsuspecting Doncic with about a minute and a half left in regulation, sending Doncic to the floor in pain and blood oozing from a cut in the back of his head.
On Green's game-tying basket, Howard appeared to grab Seth Curry with both hands, preventing the Maverick defender from getting to Green in time to prevent the shot. There was no penalty on either play.
Tatum nailed a turnaround jumper with 1.3 seconds left as the Celtics improved to 4-1 by winning their fourth consecutive game.
Walker scored 23 of his 33 points in the second half for his new team. He came into the game with back-to-back 32 point performances but this was his best game since signing with Boston as a free agent.
Gordon Hayward finished with 13 points and nine rebounds in a back and forth game that included 24 lead changes.
After Morris' basket from beyond the arc, the Celtics called timeout and Marcus Smart inbounded the ball to Tatum in the corner for the game-winner.
- Harden cools off -
Also, Brooklyn slowed down red-hot Houston Rockets star James Harden by using a stingy defence and a well balanced offensive attack for a 123-116 victory.
Two nights after scoring 59 points Harden shot just 10 of 31 from the field and missed all but two of the 16 threes he attempted. Harden, came into the game averaging 36.8 points, still finished with 36.
Russell Westbrook added 27 points, eight assists and seven rebounds.
Neither Harden nor Nets Kyrie Irving was at their best in a matchup of the NBA's two leading scorers.
Irving finished with 22 points for his first game this season under 25. He also had 10 assists.