The former Perth Glory midfielder has only played 90 minutes of game time in the past 12 months but coach John Kosmina reckons his latest signing is up to the job.

Sydney's defence has been left in tatters by Mark Rudan's transfer to Japan and Mark Milligan's back injury ruling him out.

Jacob Timpano is back on the long term injury list after suffering yet another recurrence of his long-term leg problem, although the club has now identified the cause of the problem and will be changing his rehabilitation programme in future.

Kosmnina is now backing Robertson to step up for the club in the unfamiliar position for the vital F3 derby.

But ex-Dundee FC star Robertson insists he is ready for the role and has the experience from his Scottish Premier League days to shine in big matches.

"I've been thrown into the deep end before," he said after training yesterday. "I've played against tough teams and in front of hostile crowds.

"We went to Parkhead to play Celtic and the place was packed. They were supposed to clinch the league title by winning that day.

"The trophy was at the ground, ready to be unveiled. That's a sink-or-swim situation, but we beat them 2-0 and I was lucky enough to get man of the match."

He added: "It isn't like I'm going to get nervous before a big game.

"I take the view that if you can step up in big games like that one against Celtic, you can step up anywhere. I'm feeling really excited about starting on Saturday.

"I've been around long enough to know this time of the season is crunch time for a lot of teams - and this is a huge game for us.

"We need to pick up something from it - preferably all three points - and even though we were beaten by Perth last week we'll take a positive attitude in against Central Coast."