Given the forward strike power in a Gold Coast side featuring Joel Porter and Bruce Djite, neither of whom played against the Mariners, any chance to get on the field and impress coach Miron Bleiberg is one to be embraced.

But not even Barisic could have imagined scoring the winner on Sunday within seconds of entering play with the youngster's goal coming at the end of a frantic four-minute period that saw three goals scored.

"I haven't seen a lot of game time so I know that when I get the chance I have to take it, which is what I tried to do and it worked out well for me," Barisic said.

"It was 1-1 when I was standing with the fourth official waiting to come on, then suddenly I was going into a match that was locked at 2-2. It was very unusual and certainly doesn't happen every day.

"After Panta (Steve Pantelidis) scored to put us up 2-1, Miron gave me some additional instructions. Then almost straight away they equalised and everything changed again.

"Miron then told me to get on there, be selfish and go for goal. Within a few seconds of being on the field I managed to do just that.

"It was a crazy few minutes and must have been great entertainment for the fans, but we were just glad to get the points against a very tough side."

Barisic, 24, took advantage of a rare mistake by Mariners skipper Alex Wilkinson as he latched onto a poor back pass, before showing enough composure to fire truly as Wilkinson desperately challenged from behind.

"I'd only just got on the field and everything happened so quickly," he said.

"When Wilkinson lost the ball I remember getting into the box and thinking he was fouling me, but fortunately I managed to hold him off and slot it away.

"It came at the end of a mad few minutes when goals were flying in, so it was a bit surreal. When I saw the ball hit the net everything went quiet, which was a bit weird, and it just made me check that I the goal had been given.

"When ten thousand people go silent it makes you think that something is wrong and time stood still for that few seconds until I realised everything was okay.

"It's strange because I had a good feeling about Sunday's game and I was itching to get on. I felt confident I would score and couldn't believe it when the chance to score was presented to me so early."

The victory sees United climb above Central Coast into third on the  A-League table. Gold Coast have not lost a game since August 29 when they suffered their only defeat of the season in a 1-0 loss to Melbourne Victory.