Latrell's potential is scary: Cordner

Sydney Roosters phenom Latrell Mitchell has been urged to discover just how good he can really be ahead of the tri-colours' monster NRL showdown with fierce rivals South Sydney.

The minor premiership and top four could go a long way to being decided during a blockbuster round 21 next weekend.

Friday night's local derby between the Roosters and ladder leaders South Sydney will have massive ramifications for both the top four and the title race.

Should the Rabbitohs win against the Roosters and Melbourne beat arch-rivals Cronulla, it will give Souths a four-point buffer at the top of the ladder.

Standing in Anthony Seibold's side's way are the Roosters, whose season continues to gain momentum after Mitchell bulldozed North Queensland on Friday night in what was their fourth win in a row.

While South Sydney hooker Damien Cook has emerged as his side's x-factor, likewise Roosters centre Mitchell has gone from strength-to-strength following his debut State of Origin series, strengthening comparisons to Greg Inglis and Mal Meninga.

In his last three games Mitchell has clocked up six tries, five linebreaks, 18 tackle busts and one try assist.

In a daunting premonition, Roosters captain Boyd Cordner said 21-year-old Mitchell doesn't yet know just how powerful and influential he can be.

"He's a player that can create something out of nothing," Cordner said.

"He's a very special talent. I don't think he knows how good he is really, which is a scary thing.

"I think he's still got a lot more development in him."

The top four race was turned upside down during a tumultuous Sunday afternoon of NRL action.

Penrith overturned a 14-point halftime deficit to run over the top of a hapless Canberra 40-31 to remain in fourth, keeping their chances alive of securing a second bite at the cherry during September.

The Sharks lost 33-32 to Manly thanks to a left-footed field goal to Daly Cherry-Evans in golden point which piled pressure on Shane Flanagan's team.

After losing their last two, the Sharks' top four hopes are quickly fading and they need a bounce back against the Storm on Sunday.

"We need to start winning," Sharks skipper Paul Gallen said.

"If we want to crack that top four, we need to string some games together and it's got to start soon - now and next week."

Meanwhile, Parramatta ensured the race to avoid the wooden spoon was alive after upsetting the Gold Coast 28-12 on Saturday.

St George Illawarra remained in fourth spot despite losing 18-12 to a Roger Tuivasa-Sheck-inspired Warriors at WIN Stadium.

The Wests Tigers kept their faint top eight hopes alive with a 25-18 win over Newcastle at McDonald Jones Stadium.

Canterbury turned in their best performance of the season with a 36-22 romp over Brisbane on Thursday night.