James Harden says the Brooklyn Nets must be "more engaged" on defense after a second successive loss to the Cleveland Cavaliers again exposed their weakness.

According to Harden, who made the point repeatedly in a brisk post-game news conference, it is communication that the Nets need to work on to reach their potential.

With Harden, Kyrie Irving and Kevin Durant in their ranks, such potential is obviously something very special indeed.

But as Harden stressed, all their scoring power will be negated if they leak too many points to the opposition, as they did in sliding to Friday's 125-113 defeat.

It was a result that sent Brooklyn sliding to 9-8 this season, and recent arrival Harden hopes there can be improvement in the games ahead.

He said: "Our communication, our position, we never really had practice time so we're learning on the fly.

"It's just constant effort. We've got to be more accurate on loose basketballs, do a better job on rebounding basketballs, and then do a better job of keeping our man in front of us.

"There are some of the aspects we can get better on. If we do those things, then the schemes and all those plays we can figure those out later, the principles are those small things.

"I've got to be a little more aggressive. Honestly, our problem isn't offense. We scored 113 points tonight and even in the last game it was more than enough to win the game.

"Defensively we have to be more engaged."

That last game, to which Harden referred, was the 147-135 double-overtime loss to the Cavs.

The former Houston Rockets player and eight-time All-Star said it is "little tweaks" that are required, starting from Saturday's clash with the Miami Heat.

"Individually, our communication from the other four guys - the four guys that aren't guarding the ball - has to communicate on where the help is, where to send the dribbler, and just communicate, have each other's back," Harden said.

"Once our communication from all five guys are in sync, our defense will be that much better.

"But it seems like we're on an island out there and we have to all do a better job, including myself, of communicating and helping each other out defensively and that will happen."

With Durant absent after an Achilles problem, Harden bagged 19 points and 11 assists and Irving scored a game-high 38 points.

And while the combination of the three Nets superstars seems sure to click, Harden knows what the priority must be.

"As much as we can talk about scoring - we're very good at scoring - we've got to round up some stops and once we get that going we'll be in the lead on both sides of the ball, but right now our problem is defense," Harden said.

"[On Saturday] we've got another chance to get better."