MIAMI (AFP) - Cleveland superstar LeBron James acknowledged the latest Cavaliers loss in Miami was "concerning" with the NBA playoffs fast approaching.

The Cavaliers still own the top seed in the Eastern Conference, but the Toronto Raptors are inching closer, and the Cavs' 122-101 loss to the Heat on Saturday night didn't help.

"The way they've beat us here is a little concerning," said James, who is now 0-4 at Miami since he departed the Heat after sparking the Florida outfit to two NBA titles, returning to the Cavaliers with the avowed aim of bringing a championship to his home state.

"It's not about the win or loss," he said. "It's how you win or lose and we didn't play with the biggest potential we could play with."

The Cavaliers are 19-9 and fourth in the league in offensive efficiency since Tyronn Lue took over as coach in place of David Blatt in January.

However, they are 15th in defensive efficiency.

"We know we have to finish off the season as well as we can and then get ready for the post-season," James said. "You'd like to be playing extremely well in late February going into March. But if not, you just work your habits and continue to work on what you've been doing over the season."