Brooklyn Nets head coach Steve Nash said the return of superstar James Harden will "change everything" after the NBA championship hopefuls slumped to a fourth consecutive defeat.

The star-studded Nets – playing without former MVP Harden again due to a hamstring injury – fell to the Dallas Mavericks 113-109 on Thursday.

A game-high 45 points from Kyrie Irving and Kevin Durant's 20 points were not enough for the Nets, who are two and a half games behind the Philadelphia 76ers in the race of the Eastern Conference top seed ahead of the playoffs.

Harden has not played since April 5 but is "very confident" he will return to action before the postseason gets underway.

Reflecting on the result, Nash – whose Nets are eyeing their maiden title – told reporters: "We're just trying to get better every day. We can't really control the injuries. We're getting healthy bodies back, we've got the most guys I think we've had all year right now that are available; so that's positive. Trying to figure out some rotations and combinations.

"Obviously, James comes back at some point and changes everything again. But we're trying to just get better. We're trying to get more familiar with what we're trying to do, trying to get better at our principles and get a better understanding between one another.

"As I said, a lot of these teams have been in the last two, three, four years in a row. We're just getting to know each other; a lot of our guys have missed a lot of season. So trying to gain that understanding, that continuity is what we're after right now. We're going through a tough stretch, we're not playing really well, we're not playing really sharp. We were right in it today, we had our chances for sure; we've had our chances in the last three games.

"So what is it that can get us over the hump? I think the first thing is for us to continue to stay strong mentally, to pick each other up, to realise we got a lot of work to do. We keep working, we don't let this take the wind out of our sails and we'll improve and get better."

While Irving starred, Durant was below his best against the Mavericks as he finished seven-for-21 shooting, having missed all four of his three-point attempts on the road.

"Kevin didn't have a great rhythm tonight, especially in the second half. He normally can get to his spots and convert. He just wasn't in a great rhythm. Some nights it's just going to happen," said Nash.

"We're all going to have poor shooting performances or nights where we don't quite have a rhythm. And then the defense, we made some mistakes. I thought the third-quarter defense was really good. In the fourth quarter, we made a few mistakes and they made a few plays, but I think there's a lot to build on. We can look at the tape, continue to build, continue to grow."

Durant added: "It's trust my work and most of the times a mentality switch on what I need to do to be more effective and more efficient. Tonight I tried shots that I shouldn't have tried. I shot over a double-team in the fourth quarter. I shot a runner going to the left, just trying to get into the game scoring-wise, and sometimes that pushes me out of the game when I try those tough ones, but it's all a learning experience.

"I'm glad it's happening now for us instead of in a couple weeks, and hopefully we build off of this and keep growing, and I hope we feel this pain, I guess, from losing, feeling like we're not where we want to be. I like this position for us, and I think it's gonna make us better as we continue to keep watching film, going through practice, going through shootarounds and then playing in games."