Shane Smeltz's pair of goals from the penalty spot either side of half-time fired Gold Coast to a two-goal buffer, before Perth rallied late with a goal through 17-year-old Adam Taggart after retiring veteran Jamie Harnwell flicked on a long ball.

Despite plenty of pressure, there was no dream ending for Harnwell, who was playing his final ever game for Glory, but stand-in coach Stuart Munro was impressed by his young brigade - particularly Taggart - who represent the future for the club.

"I thought Adam (Taggart) did really well," Munro told Fox Sports after the game. "His movement up forward was terrific for us. He chased lost causes all day.

"Him, Tommy Amphlett and Josh Risdon they're the future of the club. Fergie's made no secret of that in the last few weeks, when all seems a little bit lost you've got to find something in the ashes and for us it was these young players who we've got to give some game-time knowing they're the future for this club."

Gold Coast coach Miron Bleiberg agreed Perth's youngsters were impressive.

"Perth should be happy that maybe that's their future," Bleiberg said. "In the end they showed pace and they showed grit and played much better than they did at the beginning.

"That's the light at the end of the tunnel if you're a Perth supporter."

Bleiberg added he was impressed Gold Coast withstood Perth's late onslaught.

"You're in full control, you feel you're the better team and then one goal with the encouragement of the crowd, they play like a twelfth man. That's how things change in soccer, it's the beauty of the game," he said.

"Then it's up to the other team to keep a cool head and possession or buckle. We didn't buckle, we kept a cool head and we kept possession."

The victory keeps United in the hunt for a top-two finish with a clash against second-placed Central Coast to come in midweek, but Bleiberg wasn't getting carried away with the prospect.

"Every game counts and three points puts us in a good position to challenge for fourth, third or maybe even second if you want to be extremely optimistic," he said.

Bleiberg also revealed he may have lost forward Golgol Mebrahtu for the rest of the season after he injured his shoulder when he won Gold Coast's first penalty.

"He fell on his shoulder and hurt his AC. According to the Perth doctor, which I heard is a shoulder specialist, is anything around six to eight weeks," Bleiberg said.

Munro said he was disappointed Glory couldn't give Harnwell a winning send-off.

"Today was about Jamie Harnwell," he said. "We're delighted with the career he's had but obviously not that we didn't send him away with a win today. We badly wanted to win for the supporters and Jamie today and it didn't happen."

Harnwell added: "The club has always been there for me. It's been a rollercoaster at times and unfortunately today didn't have the fairytale finish.

"It's very sad. What more can you say, it's the end."