Los Angeles Lakers superstar LeBron James said he has not been surprised by the Philadelphia 76ers, who loom as a serious NBA contender in the Eastern Conference.

James experienced the 76ers first hand on Sunday - the Lakers outclassed in a 143-120 defeat at Wells Fargo Center in Philadelphia.

Already boasting All-Star duo Joel Embiid (37 points, 14 rebounds) and Ben Simmons (8 points), as well as Jimmy Butler (15 points) and JJ Redick (21 points), the 76ers are now seen as genuine championship challengers after acquiring Tobias Harris (22 points) in the blockbuster trade from the Los Angeles Clippers before Thursday's deadline.

Mike Scott, Boban Marjanovic, Jonathon Simmons and James Ennis were also brought in to strengthen Philadelphia's depth.

After the 76ers improved to 36-20 in the Eastern Conference, James - who was pursued by Philadelphia before he joined the Lakers in the offseason - told reporters: "I thought they were going to be very good anyway before they made any moves, before the season even started.

"And they've made a bunch of moves to improve their club."

Lakers president Magic Johnson was in attendance and the Hall of Famer had a message for the east.

"The East better watch out," said Johnson. "This is a stacked team."

Kyle Kuzma starred for the Lakers on the road, posting 39 points - 23 of those coming in the first quarter.

James, meanwhile, finished with 18 points, 10 rebounds and nine assists as the Lakers dropped to 28-28 to be 10th in the Western Conference and two and a half games outside the playoff spots.

"We had too many breakdowns," James said. "Way too many breakdowns. I mean we scored the ball as well as you can score the ball, especially in that first quarter, but we gave up too many paint points.

"We didn’t keep the floor shrunk and make them make many outside jumpers to begin the game, and once they started getting to the paint it kind of opened up everything else."