Kyle Flanagan has backed Lachlan Ilias to prove a point against South Sydney, arguing the motivation alone will bring out the best in his halves partner.

Ilias's first competition match against his old club will headline a grudge match for he and Damien Cook at St George Illawarra, after last year's Rabbitohs exits.

But while Cook was the Rabbitohs' best hooker of the 21st century before he was tapped on the shoulder by club officials last June, all eyes will be on Ilias.

That in itself will be nothing new for the halfback, who was burdened with the weight of expectation at Redfern from the moment he replaced Adam Reynolds in 2022.

After taking Souths to a preliminary final in his first year, Ilias was dropped last March, then told he was free to leave the NRL club.

The 25-year-old has already met the Rabbitohs once this year when he scored one try and set up another in the Dragons' Charity Shield win, but Saturday marks the first contest for points.

Flanagan is well versed in such situations, having previously had return bouts against Canterbury and the Sydney Roosters after differing exits from the two clubs.

And he is the first to admit Ilias may find it hard to not go out trying to prove a point at WIN Stadium.

"It can be quite hard, especially early on when it's your first time playing against them," Flanagan said.

"Playing in the Charity Shield and playing against South already might have helped him. It might have got that energy out of the way.

"But I think it can be a good thing though. If he goes out there and he goes after the game, it can definitely help him that he's got a point to prove.

"Obviously you're putting the team first and the individual second, but it's not too bad of a mindset to have."

After recovering from a broken leg suffered in NSW Cup last April, Ilias was told he'd play dummy-half this year if he remained a Rabbitoh.

Souths have had their own halves issues since his exit, with Jamie Humphreys set to keep the No.7 jersey from English import Lewis Dodd this weekend.

Ilias has spoken about the belief that he is already a better player at the Dragons, with the benefit of maturity and watching most of last year from the sidelines.

The Red V's attack showed good signs against Canterbury in their 28-20 round-one loss, but players have been told the defence must step up significantly.

"I've just been speaking to (Lachlan) about going out and playing his game and building up the back of what we did last week," Flanagan said.

"You just focus on what's next and his role here and not look in the rear-vision mirror.

"If I had advised myself five years ago, I would have said exactly that, just to focus on where you are now in the present and focus on what you can control."