The A-League has no immediate plans to install goal-line technology as debate continues to rage over a ruling in Saturday night's derby that was so tight even Wanderers hero Daniel Lopar admits he was "not 100 per cent" sure if Sydney FC were wrongly denied a goal.

On an evening when "mentality beat quality", in the words of Pirmin Schwegler, Western Sydney weathered a 90-minute storm from a vastly superior Sydney FC to secure a gritty 1-0 win at Bankwest Stadium - their first over the Sky Blues in almost three years.

But for a few millimetres, it could have been a very different story. Kosta Barbarouses's header off a corner in the 51st minute hit the inside of the post, spun across the line and was scooped up by Lopar, who immediately wagged his finger at referee Alireza Faghani to say the whole of the ball did not go over.

Speaking to reporters after the match, Lopar was a little less adamant. "I was pretty sure, but not 100 per cent," he said. "Not full, in my opinion. But that's also the luck you need on your side."