Melbourne Storm are confident their suspect left-side defence will hold up under serious pressure from South Sydney's biggest weapon Greg Inglis when the teams open the NRL finals series on Friday night.

The Rabbitohs would have watched with interest how Manly recently carved up the Storm, scoring all six of their tries down that left-hand channel through Brett Finch, Will Chambers and Sisa Waqa.

Fullback Inglis, who Melbourne skipper Cameron Smith this week described as "unstoppable", will be certain to test that side at ANZ Stadium.

Storm speedster Justin O'Neill said he thought the Manly game was a one-off and was confident Melbourne's backline could contain Inglis and his dangerous teammates led by clever halfback Adam Reynolds.

"Manly definitely targeted our left side and had a bit of success," O'Neill said.

"We've definitely learnt from our mistakes and want to fix that up.

"The areas that we had a bit of trouble in on that night we've fixed up and if Souths want to target the left side we'll do all right in defending it."

O'Neill knows former Storm boy Inglis' game well, playing outside him in his debut year in the NRL in 2010 and scoring nine tries.

"I was fortunate to play outside him and I think that's where most of my tries came from that year," the 22-year-old said.

"It was a great experience ... he's a freak.

"I learnt a lot off him and it builds your confidence as a young fella coming through to play outside someone that skilled and that good a player."

The Storm are waiting to see if Finch makes a full recovery from a sternum/shoulder injury to take his place, with England international Gareth Widdop waiting in the wings after his own comeback from injury.

"Gaz was playing great footy at the start of the year and it was unfortunate that he got injured," O'Neill said.

"We were lucky to have Finchy to fill the spot really well so I guess we'll see how he goes but Gaz is right to play."

O'Neill, who is in line for Queensland Origin selection next year, said there were similarities from their triumphant 2012 NRL season but the team wasn't relying on that.

He felt their hard-fought golden point win over Gold Coast last round was the ideal launching pad for their finals assault.

"It was a gutsy performance and more Storm-like.

"It was definitely a tough, grinding game and it was good to get a game like that under our belt coming into the finals."