Melbourne Victory head coach Kevin Muscat said concentration lapses cost his team in its 2-1 loss to Adelaide United on Friday night.
Mark Milligan's tremendous goal had drawn Victory level after Besart Berisha's penalty was saved and Baba Diawara headed the Reds into a lead at Etihad Stadium.
But George Blackwood scored a 72nd-minute winner for Adelaide, which finished with nine men after red cards to Daniel Adlung and Ben Garuccio.
Muscat said it was again lapses of concentration which proved costly for his team.
"In relation to the game, a couple of moments of lapses of concentration," he said.
"Again, we give ourselves a mountain to climb – a lapse of concentration, someone six or seven yards out on a set-piece with a free header. That's nothing else but concentration.
"We have an opportunity to score from the penalty spot and we don't and then when it seems like we've got all the ascendancy in the game, we're making all the attack, making all the play, getting forward, creating chances, we get a deserved goal and a very good goal and again, a lapse of concentration.
"We fall into a false sense of security because we get the equaliser and then just the understanding of what got us the equaliser we don't maintain.
"We're not as aggressive, we're allowing crosses to come in, they've got a body in the box and no-one is marking him and again, a lapse of concentration and you give yourself another mountain to climb."