Hemel’s win on Wednesday saw them leapfrog the Skolars into third place, but Mbu is confident his side can finish the season well.
Mbu said: “We had a very positive first half against Gloucestershire (last week).
“We’ll have to be good again this week because Oldham are a very good side.
“They keep coming from minute one to minute 80, and that’s what we’ve got to do in response.
“We’ve got to turn up on the day and deliver what we need to.”
Mbu has also praised former Great Britain winger Gareth Raynor after he scored on his Skolars debut.
Mbu said: “A neutral person watching that game wouldn’t have spotted that it was his first game with the squad. He fitted in and did what he needed to do. There’s not much more that you can ask for.”
Oldham coach Scott Naylor is facing a couple of selection headaches as Richard Lepori and Jason Boults battle to be included in Sunday’s squad.
Naylor said: “I’ve got a fully-fit squad so once again I’ll have some tough decisions to make.”