Sydney FC appealed Williams' decision to send Petkovic off for a foul on Adelaide United's Fabio Ferreira in the 87th minute with scores locked at 1-1.

Adelaide went on to win 3-1 after extra time, with FC coach Graham Arnold labelling Williams' decision an "embarrassment".

But the match review panel upheld the red card, determining no obvious error had occurred.

For it to be an obvious error for a direct red, the panel needs to decide no referee in the world would not have given even a yellow card for the incident.

It means Petkovic will miss Sydney's clash against the Brisbane Roar at Suncorp Stadium on Friday night.

But A-League boss Damien de Bohun said Williams will also sit out this week's round.

"Like everyone in the game, referees are accountable for their performances and decisions," de Bohun said in a statement.

"The referees come under enormous scrutiny by the public and media, as well as the official reviews of assessors.

"In the view of the director of referees and that of the assessors, the decision by Ben Williams to show a red card to a Sydney FC player in last night's FFA Cup match was not warranted.

"Accountability is part of improving the standard of refereeing in the A-League. If a player is dropped, the coach will work to get the player back in form as quickly as possible, and referees are no different."

Williams is one of Australia's most decorated referees, having been crowned Asian Football Confederation referee of the year last year.

He has refereed at the World Cup, Olympics and under-20 World Cup.

The 37-year-old was in charge of the 2012 Asian Champions League final and officiated in the last Asian Cup.

But he has also handed out a large number of red cards during his career.

During last season's A-League, Williams dismissed seven players – more than twice as many as any other referee in the competition, with three reds the most by anyone else.

He also sent off Brisbane Roar's Matt McKay in their opening round 2-1 loss to Adelaide.

Nine days later he was pulling out the red card again.

During the game, Arnold said the decision was an "embarrassment" after Williams had allowed play to continue and waited until Adelaide's attack had come to nothing before showing Petkovic the red card.

"I feel for the fans and the viewers, and most of all I feel sorry for the players," Arnold said after the game on Tuesday night.

"I made my feelings known in the emotion of the game.

"It's the first time I've seen a red card given after play on ... they both got up and chased the ball."

Former Socceroos goalkeeper Mark Bosnich was also critical of Williams' decision.

"We had the ridiculous situation of Ben Williams giving a red card to Nikola Petkovic, which everybody and their dog and millions on social media all thought the same thing – that it was one of the most ridiculous red cards that I've seen in a very, very long time," Bosnich said on Fox Sports.

"[Football Federation Australia] should be thinking ... in the future, because we've had a few controversial incidents recently, they might start thinking about allowing [referees] to speak to the press afterwards to explain their side of the story, because for the life of me I don't understand why he gave that guy a red card."