SYDNEY Swans coach Paul Roos expects the Western Bulldogs to take confidence into Friday night's semi-final clash at the MCG, given the Dogs' dominance in their other two encounters this season.

The Bulldogs beat the Swans by 18 points in round seven and 16 points in round 18, but have only posted one victory in five matches since.

Speaking on arrival at Melbourne Airport on Thursday afternoon, Roos wouldn't subscribe to views that the Bulldogs were vulnerable after their recent run.

"It's a new ball game, but they'll go in with some confidence," he said.

"We know they're a good team. You don't finish third on the ladder if you can't play.

"We know they're a good side and we're going to have to play better than we have done in the past couple of games (against them)."

Roos wasn't buying into the Swans' underdog status either.

"Underdogs, favourites – that's more for the bookies. We'd like to win. We hope we can win but whether you're favourite or underdog at this time of year is almost irrelevant."

However, Roos did admit that the finals experience of his more senior campaigners had helped in the victory over North Melbourne in the elimination final.

"It certainly helped us last week and certainly it was the senior players that really stood up.

"Leo Barry had a great game for the whole game and (with) Ryan O'Keefe were probably two of our most consistent players.

"Then Kirky's second half (was good) and Jude and guys like that, so it certainly helped us last week. Whether it matters much tomorrow night, time will tell."

The Swans have made no changes to the side that defeated North Melbourne by 35 points in last weekend's elimination final, though Roos said the fitness of midfielder Luke Ablett would be monitored over the next 24 hours.

His belief also extended to support for the Swans in the MCG stands, echoing counterpart Rodney Eade's Thursday morning call for fans to get along to the game.

Just 19,127 people saw the Swans beat North Melbourne and Roos looks forward to a stronger crowd, given the club's South Melbourne heritage and the numbers that savoured its 2005 premiership triumph.

"I'm sure there's going to be a big crowd tomorrow night. We have a lot of supporters down here, which is great," Roos said.

"We enjoy playing in Melbourne, we get really good support down here – I'm reading 50-55,000.

"We love playing at the MCG, it's a fantastic venue."