GEELONG captain Joel Selwood says the Cats must improve their defensive work if they are to mount a serious challenge for this year's premiership.

Chris Scott's team is conceding an average of 91.6 points per game, which makes it the 10th-best defensive team in the competition.

The team with the stingiest backline, Fremantle, has conceded just 66.5 points per match.

The situation was brought into focus by Geelong's collapse against the Brisbane Lions at the Gabba on Sunday.

The Cats led by 52 points during the third quarter, only to allow the Lions to boot eight goals in the final term and snatch a five-point win.

"I think we see that the best sides are usually the best defensive sides and we're just working towards it," Selwood said at Melbourne Airport on Monday after arriving back from Queensland.

"We know where we need to be and we've got to make our way there. That's by working hard at training and getting it right."

Geelong's players and coaches will review the shock loss when they gather at Simonds Stadium on Tuesday.

"It was a really poor last quarter," Selwood said. "We'll put out hands up and we've to make sure we work out a way to become better from this.

"We'll work out what we did wrong and what we did right. We did a lot of things wrong in the game, but we also did a lot of things right.

"Footy's a tough game and we expected Brisbane to be a really tough side. We saw what they did against Essendon, so we knew we were going up there for a hard game."

It's not all bad for the Cats. They have a 10-2 record and are just one win behind top side Hawthorn.

But, as Scott has admitted on a number of occasions, their form has not been particularly impressive in recent weeks.

"We know that we haven't been playing that well," Selwood said. "We've been playing patchy footy all year.

"It is a concern and we're working on it at training. We'll make sure that we continue to work on it."

Geelong has two tough weeks to come. It plays Fremantle at Simonds Stadium on Saturday night, then takes on the Hawks the following weekend.

Adam McNicol covers Geelong news for AFL.com.au. Follow him on Twitter at @AFL_AdamMcNicol