After Sydney took the lead early via a contentious free kick to de Jong, both sides scored in the five minutes after the break to set the match alight at Kogarah.

However Adelaide couldn't find a levelling goal despite having 56 per cent of the ball, with Sydney goalkeeper Andrew Redmayne pulling off a diving save to his right to deny Ryan Kitto in stoppage time to wrap up the win.

But the drama had started in the 11th minute when referee Adam Kersey pulled up Nikola Mileusnic for bringing down de Jong from behind, just outside the box, as the Sky Blues forward attempted an intercept.

Replays showed Mileusnic had appeared to make contact with the ball first, but it mattered little when de Jong curved the ball into the top left of the net and past the flat-footed goalkeeper Paul Izzo.

"It was a clear tackle and no foul," Adelaide coach Marco Kurz said.

"I am 100 per cent sure it was a free kick.But for me as a coach I start earlier - we didn't clear the ball (in the lead up).

"But it's a clear tackle and I don't know what the referee decided."

But Sydney coach Steve Corica disagreed.

"No chance," he said of the suggestion it should have been let go.

"What is he supposed to do? He can't stay on his feet if the defender is sliding in?"

Sydney later looked to have the match well within their control when Tratt neatly headed a Brandon O'Neill corner goalward to make it 2-0 in the 48th minute.

However Adelaide hit back just two moments later through Craig Goodwin from the penalty spot, after George Blackwood went down in the box following minimal contact from Aaron Calver.

"I'm not even sure if that was a penalty ... I thought he made a bit of a meal of it," Corica said.

Again, the two coaches disagreed on the call.

"When the free kick was a free kick, then that was 100 million per cent a penalty," Kurz said.

"And without the free kick, it was still a penalty."

Sydney then had opportunities to win it through both de Jong and Alex Brosque, the former denied by the VAR when Adam Le Fondre was offside the and the latter after he sent one wide.

Meanwhile Adelaide's best chance came in the final minute of stoppage time after some nice lead up play from Blackwood and Michael Marrone, before Redmayne dived low and to his right to ensure three points for Sydney.

The result kept Sydney in third spot after their mid-week loss to ladder-leaders Perth, while Adelaide's loss was their first in five weeks as they sit safely in sixth.

Australian Associated Press