Stunned coach John Longmire fears Sydney got ahead of themselves during arguably the most embarrassing loss of his tenure.

The Swans held a 29-point lead over Gold Coast at quarter-time, seemingly marching towards the percentage-boosting win that every pundit predicted.

The Suns booted the next eight goals of the contest, steamrolling their way to a 24-point win over Sydney.

The greatest upset in 23 years, according to betting markets at least, is a hammer blow to Sydney’s top-four hopes and may potentially cost them a finals berth.

The Swans attempted to roll out more razzle-dazzle football in the second term, much to Longmire’s disbelief, playing on regularly and putting teammates under the pump.

A stack of turnovers and errors followed, helping Gold Coast kick six goals to zip in the second quarter.

“It’s hard to deny,” Longmire said when asked if his charges got ahead of themselves at quarter-time.

“You’d like to think not, but you look at the evidence and the evidence suggests that.

“This game’s got an amazing ability to punch you on the nose when you think you’re on top of your game.

“We copped a whack.”

The 2012 premiership coach hoped commentary about the Swans using this weekend to gain some percentage didn’t affect his players.

“I guarantee it wasn’t spoken about inside the club. I’ve been around long enough not to fall for that,” Longmire said.

“We just need to make sure that chatter doesn’t impact how we play, if it did.”

Longmire will be keen to make changes but an injury crisis will limit what he can do.

Speedster Gary Rohan, who loomed as a likely inclusion, suffered a suspected broken hand in the NEAFL curtain-raiser.

“We ended up with nine listed players in our reserves today … we’ll find a way,” Longmire said.