Expect the Swans to be back to their hard-nosed, defensive best in Saturday's Sydney Derby, despite the missing faces from its backline, says Nick Blakey.

The 23-year-old says playing crosstown rivals Greater Western Sydney is the perfect chance to rectify last week's loss, regardless of the names on the team sheet.

With a defensive group missing key planks Tom and Paddy McCartin, along with co-captain Dane Rampe in last week's Round 6 match against Geelong, the red and white suffered a heavy defeat.

That won't happen against the Giants, Blakey told AFL.com.au, with the Swans now also missing Robbie Fox (concussion), but regaining Tom McCartin.

"It's obviously been shaken up a bit losing Tommy and Paddy and Ramps," Blakey said of the defensive unit.

"We've always had that 'next man up' mentality, though. The boys have been playing well in VFL that came in and can do a job.

"We were good against Richmond the week before, but it wasn't there on the weekend. No matter who plays we expect that defensive mentality."

Callum Mills started in defence against the Cats, a role he played the first five years of his career, while Harry Cunningham returned there from the forward line and youngster Will Gould came on as a substitute.

The Swans have now had another week to gain continuity in that half of the ground, getting through a strong main session on Thursday.

"It's obviously tough when you haven't played a whole lot of football with the group, but Gouldy has been at the club three years, Harry Cunningham has been down there forever, everyone knows how we defend, we just haven't been a back six together," Blakey said.

"It is there, everyone knows what we're doing … I'm sure it would be nice having Paddy and Ramps out there, but it is what it is, and we've got to be ready.

"It's a good challenge for us.

"We were well beaten by Geelong's forward line … as defenders we'll have to be on our game and it's a good chance for us to bounce back."

Blakey said it was the desire to be the kings of Sydney that drove the rivalry between the Swans and Giants.

Sydney has a 15-9 head-to-head advantage, winning both contests in 2022. The two sides will play for the Lifeline Cup come Saturday to raise funds and awareness for mental health and suicide prevention in Australia. 

"It’s a big game no doubt," Blakey said.

"We know a lot of the Giants' boys, we live in similar areas, so the games are always big games. A lot of us know what we do well as players and that's why they're always similar games, very contested and very close.

"The more we play the bigger the rivalry is getting."

Blakey looms as a key piece for the home team, averaging a career-high 22 disposals a game.

He expected a tight contest from Adam Kingsley's 2-4 team.

"They've been in every game they've played and probably been stiff to lose a few," he said.

"They've got quality players all over the park; forwards that can all kick goals, a midfield that is elite and they've got a really good defensive system.

"It's a new group coming from the when the rivalry started - a new group for us Swans and a new group for the Giants, but nothing has changed in that hunger to win.

"As much as we were disappointed against Geelong, that's the good thing about footy, we have another chance this week to get back to doing what we do well.

"And I'm sure we will."

The Sydney Swans are gearing up to go head-to-head with the GWS Giants in Derby XXV this weekend. The cross-town rivalry will be reignited this Saturday at 2.10pm. Tickets are on sale now – get yours today!