The spotkick was awarded after Mariners substitute Patricio Perez dashed into the box before falling after only slight contact appeared to be made with Sydney keeper Liam Reddy.

Reddy was sent off for the challenge, while Perez dusted himself off to score the crucial equaliser on 73 minutes.

"I don't think there was anything in it," Musialik said. "It's just unfortunate they got a penalty for it.

"Especially the situation we're in, we've not had the best start to our season, we really needed to win this game, so to have a decision like that it's just frustrating."

Sydney coach Vitezslav Lavicka said he was 'upset' and 'disappointed' by the result, which leaves the reigning champions with just two points from their first four matches this season.

"The whole team are very disappointed. I am upset," Lavicka said. "I don't know what to say at this time."

The Czech tactician, though, was enthused by his team's performance and effort.

"We proved that we can deliver good individual performances and a good team performance," he said.

"Full credit to the players, they gave it everything. We're all frustrated."

Musialik added: "We're not happy at all. We've had a slow start to the season and needed the win so to something like that go against us is difficult to deal with.

"We improved our performances from the past two weeks. We're heading in the right direction, it's just important we get over this disappointment and look forward to next week."

He added: "There's not a lack of confidence. We definitely believe in our ability.

"It's just little things aren't falling our way. We've just got to keep working hard and we'll come out of this for sure."

Sydney's next A-League match is at home to Adelaide United next Saturday.