Dreaming big, playmaker Sam Walker credits the Sydney Roosters' narrow round-16 loss to reigning premiers Penrith as instilling the belief his side needed to make a late push for NRL title glory.

On a drizzly night in the week before the bye last month, an understrength Roosters took it up to the Panthers, who had only lost one game to that point this season.

A late try to Api Koroisau sealed the win for Penrith and consigned the Roosters to a four-game losing streak that, from the outside, appeared to threaten their finals hopes.

But internally, the defeat proved more helpful for the Roosters in the long-run than a win likely would have.

"We played some good footy before the bye but we didn't get the results," Walker told AAP.

"But we had a lot of belief after that Penrith game. I think going into the bye, everyone sort of narrowed their focus on the job at hand."

A difficult draw beckoned but the Roosters regrouped and have not lost since.

Three of their five wins came against sides placed higher on the ladder, including premiership hopefuls North Queensland and Brisbane.

Suddenly, the struggling Roosters were a chance at clawing back into the top eight.

But for the Tricolours themselves, there's been nothing sudden about the ascent into finals calculations.

"We had that belief all along," Walker said.

"I don't think it really mattered where we were on the ladder or how we were going five or six weeks ago.

"For us, it was just about trying to play our best footy and I think we're finally getting there now.

"It's taken a lot longer now than we hoped or expected but if there's a time when you want to be starting to peak, it's definitely now."

The Roosters' finals fate is not yet sealed, though.

Given ninth-placed Canberra's easier draw, the Roosters will likely need to win two of their remaining games, against Wests Tigers, Melbourne and South Sydney, to qualify.

But if the Roosters can do that, Walker has no doubt this could be the first year in the NRL era that a side from outside the top four hoists the trophy aloft.

"It doesn't matter where in the eight we finish, whether inside the top four or outside the top four, we're not here to take part. We want to win this comp," he said.

"Our results the last couple of weeks are definitely building towards something special.

"(Our belief) has definitely paid dividends."