WHEN he considered how good the Western Bulldogs' defence was against Carlton in round 16, compared to how bad it was against North Melbourne a week later, Robert Murphy found himself struggling to comprehend his team's dramatic turnaround.

Having restricted the Blues to 52 inside-50s and 24 scoring shots, the Dogs were shredded by the Kangaroos, conceding 68 inside-50s and 37 scoring shots in their 31-point loss.

"I guess I'm pretty gutted to be honest," Murphy said. "Last week was probably the most cohesive we’ve been as a team for a couple of years.

"This week was a polar opposite and we're pretty down about it."

The Bulldogs looked set to snatch a dramatic win when they fought back from 33 points down and hit the front early in the final quarter.

However, they fell away late in the contest and now face the prospect of needing to win five of their last six games to make the finals.

"I think fitness-wise, we had the ability to run over them," Murphy said. "Fitness certainly wasn't the problem in the end.

"Not taking anything away from North Melbourne, they were absolutely super today, but I'm searching for answers as to what happened to us."

Murphy collected 21 possessions and kicked a goal while floating across half-back.

But he was one of many Bulldogs players to be caught out by the pace and skill of the Kangaroos, who looked a completely different side to the one that was thrashed by Collingwood a week earlier.

"When you talk about polar opposites, that's probably the best they've played for a couple of years," Murphy said.

"I think our pressure was off too. Games are won and lost on how much pressure you can apply to the opposition and theirs was better than ours.

"That's what we'll have to talk about when we go over the game this week. Why was there pressure so much better than ours?

"They had 68 inside-50s and no team's going to lose many games when you get that sort of number."

The Dogs must now regroup before taking on the eighth-placed Sydney Swans at the SCG next Saturday.

"The great thing is that in six days we get the chance, up in Sydney, to rectify it," Murphy said.

"We can't sit around moaning about it. We've got to get on with it."