United opened the campaign with two draws but have won their last three games, including back-to-back victories on the road, and bagging three goals in each of their wins.

Perhaps more astonishing is that United have achieved all of this without: a club owner and under the operation of the FFA, a major sponsor, a marquee signing and under the guidance of Coolen who only had two weeks to prepare his squad before the season kicked off.

Coolen admitted United's success so far has been unexpected and he isn't sure if the Reds will be able to maintain such a high standard for the entire season.

The Dutchman acknowledged though, United's confidence is sky high after convincingly disposing of reigning champions Sydney FC last week, and is hoping the Reds' impressive form continues against Newcastle Jets on Saturday night at Hindmarsh Stadium.

"It surprised me in a positive way," he said.

"This is a question every week, can we continue the way we're playing now. No one suspected that we would play at that level, but we did and the next step is now, we play a home game and everybody expects more from us.

"We've done a lot of work and done well at every training session, and every game is getting better and better.

"If you continue this way there isn't much to say anymore... but we will find some details where we can do better and there's always something to be better at than last week.

"The season has just started and we're doing well, we're playing well... we can't win every game but we start the game in our head trying to win the game and that's a positive.

"You can't play 31 or 32 games at the level we're at now, it's not that easy. I can't give you an answer if we will continue this way, we will see in the future, I hope so."

When Coolen took over from Aurelio Vidmar in mid-July he inherited a depleted squad that, through injury, was missing the likes of captain Travis Dodd, Robert Cornthwaite, Fabian Barbiero and Lloyd Owusu before losing Nigel Boogaard to a long-term ankle injury in Round 2.

The United coach said he is eagerly anticipating the return of a fit and full squad before admitting his reluctance to change a winning team ahead of the clash with the Jets.

"I'm really looking forward to when the full squad is available," he said. "It will take a couple of more weeks.

"Yes, there's no reason to change it. Even the system, we may change some minor details as we're playing a home game this week.

"We have to win so little details may be different from last week. But we'll go with the same system, with the same players, it's not necessary to change anything.

"We have to win tomorrow, we know that and we have to handle that. For me it's another challenge, how my team will react in that situation. What I saw last week is that we have a lot of confidence.

"This week has been the highest level I have seen from our team. It's doesn't mean they are going to do it on the match, but this week we've trained well. It gives me a lot of confidence, it gives the players a lot of confidence."