The Leon Cameron-coached club, who fell to Richmond in last season's grand final, suffered one of the most disappointing defeats of the South Warrnambool export's tenure as coach on Thursday night.

The Giants were powerless as cross-town rival Sydney blazed away to a 41-point win at Optus Stadium.

It poses significant questions about Greater Western Sydney's ability to challenge for the AFL premiership this season.

Just holding on to eighth place, last season's grand final appearance feels like a distant dream.

Cameron is a realist and spoke candidly after the defeat. He acknowledged the effort was poor and didn't shy away from the fact improvement was desperately needed if his men were to beat West Coast on Sunday week.

"We need to have some home truths in the coming days in the review and clearly that's not going to be a good review," he said.

"We need to cop our right whack because one team turned up and the other didn't tonight and that's really disappointing. We've got nine days to prepare for a huge challenge."

"Clearly you guys (media) are not silly and neither am I.

"We're off the mark and we hover around that 7th-10th spot for a reason. If we serve up that tripe there's going to be inconsistent performances like we've had for the majority of the year.

"We've got a lot of work to do over the next six weeks if we're even considering playing finals."

There's no shortage of talent in GWS' ranks - that's a proven fact.

But if finals is to be played, effort is going to need to rise.

Cameron signed a contract extension about a fortnight ago so his future is safe.

It should be, having made a grand final last year and patience with coaches often pays dividends - see Port Adelaide's Ken Hinkley as an example.

But coaches can only do so much. It's time for GWS' players to actually come good on the gameplan and start winning.

The talent is there, so show it, or finals may be ripped away.