Without a top-four scalp all season, the eighth-placed Sharks accept there's no better time to knock over a premiership heavyweight than on Saturday night at the SCG.

But even if they don't, Johnson rubbished suggestions the Sharks loom as finals fodder amid increasing talk that the title race has been reduced to a race between the Roosters, Penrith and Melbourne.

"Any time you get to play against quality opposition, it's always a good challenge and obviously those sorts of headlines, that external noise is coming from you lot," the in-form playmaker said on Wednesday.

"We haven't once spoken about anything like that or bought into any of that sort of thing.

"We're just focused on trying to build each weekend and it's a good opportunity for us this weekend to take another step forward."

Johnson, who tops the league with 21 try assists in 2020 despite sitting out several games through injury, insisted there was genuine belief within the Cronulla dressing room that the Sharks could make a run at the title.

"The fact that we were able to cement a semi-final spot with a couple of weeks left in the comp shows that we're showing up," said the New Zealand international and one-time Golden Boot winner.

"It's been an interesting season and I think the teams reflected in the top eight are probably the teams who have best handled it, so you've got to take confidence from that.

"We show up here, walk through these gates with a mindset and an attitude to be better and apply ourselves while we're in these gates.

"Today's no different."

While the top eight was settled with Cronulla's victory over the Warriors on Sunday night, the exact make-up remains uncertain.

An upset victory over the Roosters at the SCG could alive keep the Sharks' hopes of a "home" final in the first week of the playoffs, though not at Shark Park, which remains out of action.

Australian Associated Press