With three losses in their past four matches, you could forgive Adelaide United coach Rini Coolen for being a bit anxious even though his side sits second on the table.

The Reds were the talk of the A-League just over two weeks ago but have now fallen back with the rest of the pack after suffering some less than impressive defeats.

Coolen is aware that his team needs to step up following their 3-1 loss to the previously bottom Newcastle Jets on Saturday night and hopes it starts against Melbourne Heart this Friday.

"It wasn't a good game," Coolen said.

"We lost it in the first 15 minutes, defensively it wasn't good. It's not just one person, it's the way we have to defend as a team, so we're not happy with the way we played.

"We have to improve if we are going to stay in the position where we are now, that's the next challenge. It's not easy to come top of the ladder, it's even harder to stay there and you have to improve as a team, so there are some problems at this moment, but we have to accept it and go on with what we're doing, stay with our confidence and work from week to week, and our next challenge is Friday against Melbourne Heart."