AFTER an unbeaten first five weeks of the season, Geelong is playing poor footy, said a frustrated Chris Scott.

Geelong was often second to the ball against Gold Coast, and struggled to contain the Suns' speed, going down by 25 points at Metricon Stadium.

Scott said Geelong needs to improve, and quickly, to stop its slump into a "mediocre side".

"We played poorly again, so we're really disappointed in that," Scott said.

"There's clear things in our game that we need to improve, we're going through a flat spot. On one level it's easy to identify and hopefully relatively quick to fix."

While declining to elaborate on what he thinks is the cause of Geelong's rapid downturn in form, Scott said the real key is how the Cats' coaching group addresses the team's issues.

"Obviously we go back to our training and review really thoroughly, but we can't as a group accept performances like that or we'll be mediocre.

"I'm optimistic we'll play well next week, because we'll do the work and make the adjustments that we deem necessary."

Geelong was dominated through the middle of the ground in its upset loss to Collingwood last week, and Gold Coast followed suit, with Jarrod Harbrow, Aaron Hall and Adam Saad streaming through the centre to put the Cats' defence under enormous pressure.

"In what was a really poor performance, we were dominated in inside-50s (71 to 48)," Scott said.

"The way they were able to get the ball, use the ball out the open side of the ground – their game is really clear.

"They want to use the free space, make the ground big and use their speed in the forward half, and they were able to play the game on their terms too often."

Captain Joel Selwood was responding emphatically to an uncharacteristically quiet game against the Magpies, before he sent alarm bells through the Cats' camp when he left the ground and went down the race halfway through the third quarter.

"He rolled his ankle, and the immediate feedback was pretty positive. He went back on the ground and was really competitive," Scott said.

"We really liked the way he was playing particularly before he rolled his ankle. His competitiveness was fantastic, and he and (Nakia) Cockatoo around the ball, they were really trying to get us going."

Key defender Lachie Henderson was a very late withdrawal, suffering a knock to the ribs in the warm up, but replacement Sam Menegola starred with three goals.

"He was a late inclusion for his debut, too, and played really well last year, so that part of it doesn’t worry him," Scott said.

"On only 60 per cent game time he was a really good player. And maybe that's something we need to look at, if we get the same output from him off 80 per cent game time it (the result) might have been a bit different."