Sloppy Sydney's clean sheets concerns

The impressive 4-1 home win over Newcastle on Friday night provisionally lifted the Sky Blues to top spot above local rival Western Sydney, who play on Saturday.

The one blot on their copybook was the concession of a soft setpiece goal with Matt Millar heading home a free-kick.

It meant Sydney have now conceded at least one goal in each of their first four A-League games for the first time since 2010.

Corica said he had addressed the lack of early season clean sheets with his players in the leadup to Friday's match.

"They all know their jobs and they work extremely hard, but we've been a little bit sloppy," Corica said.

"Conceded a couple of sloppy goals and we spoke about it and obviously we're going to improve in that, we've got a couple of new players into the system."

He has a potentially pleasant selection dilemma looming in the left back position after Sydney's bye next week.

Usual first choice left-back Michael Zullo is poised to return to full training next week and be available for their next match against Melbourne Victory, after missing the first four rounds with a leg injury.

Corica said Zullo had to prove his fitness and do a lot of work to force his way back into the team.

Paulo Retre performed well at left back on Friday and also at right-back after Socceroo Rhyan Grant was substituted and bounced back well from his costly error in last week's Sydney derby.

"I was very happy with the way we played last week and Paulo was part of that, he made a mistake, we all make mistakes," Corica said.

"I'm not going to crucify him for that, I thought tonight he was very good defensively, he was good, going forward.

'He was good on the left hand side but he did well as well when he switched over when Rhyan came off and he played on the right hand side,

"He's a very valuable player for us, he can play in many positions, which is very good."