The cap came off and so did the pressure as Gold Coast United ended a dreadful fortnight with a 1-0 triumph over A-League frontrunners Sydney FC on Saturday night.

After conceding eight goals in losses to the two bottom-placed teams, United dramatically turned their form on its head with a dominant display at Skilled Park.

A fired-up Jason Culina epitomised Gold Coast's turnaround with a top-shelf performance at a time his Socceroos' position and future in the A-League were being brought into question.

Culina set up the opening goal of the game in the 36th minute with a pin-point cross to star striker Shane Smeltz who clinically headed home his 11th goal of the season.

The club's captain and marquee man immediately released his pent-up frustration by knocking over two advertising hoardings behind the goals while Smeltz dished out the same treatment to the corner flag.

Unable to stay out of the spotlight, Culina's blood boiled over in a heated exchange with Stuart Musialik and both were yellow carded.

Out-of-sorts Sydney copped three first half bookings and they never seemed to recover from the early loss of skipper Steve Corica after landing awkwardly from a challenge with Steve Pantelidis.

The Sky Blues - coming off successive wins over Brisbane and Wellington - lost their early momentum with their captain and the Coast grew in confidence as the game wore on.

While the visitors were on the ropes at halftime, the Coast were unable to add to their tally.

Caravella missed a golden opportunity to double the lead two minutes later when his close-range shot from a Joel Porter cross was stopped by goalkeeper Clint Bolton.

Coast owner Clive Palmer's decision to scrap his controversial 5,000 crowd cap saw the previous week's attendance figure (2,616) doubled as 5,364 turned out at Skilled Park.

The win moves third-placed United to 23 points, two behind Sydney (25) and one behind defending champions Melbourne (24) after their 4-0 upset loss to fourth-placed Central Coast (20).

Added to Culina's class in the midfield, defender Michael Thwaite was a tower of strength as the home side effectively strangled supply to danger men Alex Brosque and Mark Bridge.

Bridge almost gave Sydney an undeserved point with an injury-time salvo which keeper Scott Higgins did well to stop.

Culina said he was proud of his team's desire and passion after a morale-sapping last fortnight.

"I knew it was there all along, it was just hiding somewhere," he said.

"We showed a lot of enthusiasm and pride in our game so it's a big weight off our shoulders, the boys played well tonight and I'm proud of them.

"We had a lot of chances tonight so it could have been even more. I think we kept them in check, we didn't give anything away."