With the scores locked at 0-0 in the 18th minute at Hindmarsh Stadium on Wednesday, Jeronimo charged into Brisbane's area before tumbling to the ground under heavy pressure from the Roar defence.

Referee Adam Kersey blew his whistle as Adelaide players appealed for a penalty only to see Jeronimo shown a yellow card for simulation.

A boisterous Hindmarsh crowd booed loudly as replays suggested the Argentine may have been clipped from behind.

The decision came back to haunt the hosts, who fell to a 1-0 defeat following a 65th-minute goal from Roar attacker Henrique.

"I think, looking at the replay, he got clipped, so that has to be a penalty doesn't it?" Kosmina said. "He was in the box and the replay shows he got fouled. He certainly didn't dive.

"He stretched for the ball and got his foot stood on, so if it's in the box it has to be a penalty."

The controversial decision has turned minds back to United's Round 4 win over Wellington, during which Jeronimo was accused of diving when bearing in on goal with Phoenix defender Ben Sigmund hot on his heels.

Jeronimo's fall after slight contact with Sigmund resulted in the New Zealand international being sent off and the 26-year-old United star being labelled 'a cheat' by Phoenix captain Andrew Durante.

Questioned whether Jeronimo's reputation may have worked against him on Wednesday, Kosmina was coy in response.

"That, funnily enough, has been suggested to me by someone who knows a lot more about refereeing than I do," Kosmina said.

Kosmina was also hesitant to comment on the performance of referee Kersey who brandished a total of eight yellow cards and was often approached by players looking for clarification on some of his decisions.

"I'm not going to comment on it because it's not worth commenting on without getting myself in trouble," he said.