Souths make history to punish sorry Manly

South Sydney put on their greatest first half in history to all but lock up a finals spot and virtually slam the door shut on Manly's season with a 56-16 flogging on Saturday.

In a 38-0 first-half demolition job at ANZ Stadium, Souths scored 26 points in 11 minutes and chalk up their biggest lead at the break in their 112-year history.

It also left Wayne Bennett hailing the 40 minutes as the best he's seen in the 853 games he's coached, celebrating his return from isolation in style.

"Certainly in the modern era it's as good of a start as I have been involved in," Bennett said.

"I was thinking about that at one stage. Particularly against a team that is a pretty quality team."

The result leaves the NRL's top eight virtually set in stone with five rounds to play, with four points now separating Cronulla in eighth from Wests Tigers in ninth.

Manly are also four points out with a bad for-and-against, and need to win all their remaining games starting with Melbourne next week to have any hope of finals.

Their nightmare was summed up in one play just before the break, when Tevita Funa fielded a kick and passed inside only for Latrell Mitchell to charge onto it and score.

Funa had a horror night playing fullback for the first time.

He was sin-binned for hitting Alex Johnston high, with an eight-point try awarded.

Johnston was left concussed and did not return, touching the ball down for his second try in just four minutes before being taken from the field.

Mitchell also starred, setting up three first-half tries before crossing for two of his own by intercepting the Funa ball before the break and running onto a Mark Nicholls offload late.

Adam Reynolds nailed five conversions in a row from the sideline, while Tom Burgess was powerful in the middle.

The Rabbitohs could now finish the round as high as sixth, but crucially three wins clear of ninth place with a run home that includes clashes with Parramatta, Melbourne and the Sydney Roosters.

Manly meanwhile are in a complete tailspin.

The loss was their seventh in nine games since Tom Trbojevic and Dylan Walker went down, falling from title contenders to strugglers.

Saturday night's drubbing was their biggest lost since 2005, as they had just 38 per cent of the ball and had to make 86 tackles in their own half.

"They're embarrassed by it, they are hurt by it," coach Des Hasler said.

"Souths were very good, and we were very poor in parts of our game.

"It was out of control in possession ... we were a little bit inept, we didn't manage (possession) well."

After Jake Trbojevic dropped a poor pass from Danny Levi early, Manly watched the score go from 0-0 to 20-0 before their next touch of the ball.

Souths' tries included one to debutant Steven Marsters with just his third touch, while Campbell Graham also got a double on Johnston's left wing after he went off.

It wasn't until the game was well up that Manly got on the board, with two second-half tries to Rueben Garrick and one to Jack Gosiewski.

But they could also now have to face Melbourne without dangerous centre Moses Suli, who left the field with a foot injury.

Trbojevic is still not due back at fullback for another fortnight while Funa could face charges for two separate high shots.