Moments earlier, with the ball at her feet, onlookers had her in their sights.

But now the play had moved towards the other end of the field and all the eyes had followed.

The fit, athletic 16-year-old lay on her back with her eyes rolled into the back of her head.

Her heart had stopped.

A teammate was the first to notice the motionless body. It was strange for a player to have dropped to the ground like that - all on their own, not as a result of contact or injury. The girl realised something was wrong.

"Ref! Ref!" she called.

Emma, a striker for Kiama Junior Football Club's under-16s side, is recovering in hospital after collapsing during a State Cup game against Bonnet Bay on Sunday, May 17.

Her incredible revival came after a group including Steve Cavanagh - the parent of a teammate - and teen referee Max Vercoe rushed onto the field and resuscitated her.

Max, 16, had completed his first aid certification only two weeks earlier, never suspecting he would so soon be applying the knowledge. He checked for a pulse and felt none.

Mr Cavanagh breathed into Emma's mouth and Max began the compressions.

"We only did 20 because she started to come back around," Max said.

"She was kind of moaning and trying to get up.

"I was pretty shocked, a bit of adrenaline kicked in."

From the sidelines, Emma's father Shane Douglas had been following the play and didn't stir until he saw a flash of the number five on what he realised was a fallen player.

A former scuba diving instructor, his own advanced resuscitation training kicked in as he felt for his daughter's pulse, pulled her into the recovery position and tried to calm her as she took a gasping first breath and burst into tears.

"It wasn't until the next day that it hit me what had happened. It was like a tonne of bricks - she's lucky she's alive, because on the field she did pass away.

"It's still incredible because today she's physically fit. She's joking, she's laughing with her friends - she's fine."

Doctors have since diagnosed Emma with an irregular heartbeat, a condition that will require tablet medication for the rest of her life.

She remains under monitoring at Wollongong Hospital and will be transferred to RPA, where a specialist team will advise whether she will need a small pacemaker-type device implanted.

Her bedside visitors have included Max who, once the game was abandoned, quietly retreated to the sheds, got changed and rode his bike home.

"It was a relief to see [Emma] after so much stress," he said.

"Knowing that she was OK and seeing it with my own eyes was pretty great," he said.