Mannah says there have been glimpses of good performances the last few weeks, it just needs to last for 80 minutes.
"It's really important - we've got our bye after this week so it's important for us to get a win," he said.
"We've got a team which, when we put in for 80 minutes, we can compete with any team in the comp, so it's about playing with confidence and believing in ourselves."
Souths have a few star players at Origin, but Tim says whoever they put on the field will be strong.
"The important thing for us is not worrying about what they've got, but getting our backyard right.We haven't put in a complete performance the last two weeks but if we do that right then we'll be in with a chance."
Tim says the rain forecast for Sydney tomorrow won't impact their spirits and their form on the field.
"It doesn't matter about the weather to us, it's a matter of playing your best footy," he said.
"It was wet at training this morning and everyone handled that ok, so it'll be good."
Today's Ticket Blitz selling adult tickets at kids' prices of just $10means hopefully a big crowd attending at ANZ Stadium, and Tim says it's great to celebrate our junior league.
"I'm a local junior and I know the effort this club puts into the junior system; it's something I appreciated growing up, so it's nice to be something I can help give back to the junior league," he said.
"We've got a really strong junior base and it's a comp we should be proud of and help build."
Click here to buy tickets to tomorrow's game at discounted prices!