The 27-year-old knows Forest will be under pressure at Elland Road, with Leeds on a fine run of form and aiming to hunt down those above them - including Mancienne's side.
And the fact Nottingham Forest themselves have been achieving results under new boss Dougie Freedman makes for added pressure.
Mancienne, however, is confident Forest will be okay as long as they keep doing what they have been of late - despite the impressive resurgence of Neil Redfearn's men.
“Leeds are going to work hard. They’ll want to put us under pressure, especially when we’re on a bit of a run - everyone wants to beat you," he told Forest Player.
“I’m expecting it to be a difficult game but, if we keep doing what we’ve been doing in the last few games, I think we’ll be alright.”
Aside from the Leeds clash, Mancienne also says he's delighted with how his time at the City Ground has gone so far.
The 27-year-old joined Nottingham Forest this campaign and believes the Championship side boast Premier League quality throughout their infrastructure.
"I’ve really enjoyed my time and I’m looking forward to spending longer here," he said.
“Forest are a top club. The facilities and everything are of Premier League quality. Compared to every other club I’ve been at, the professionalism of the people that work here is top class.”
Going into Saturday's game, Leeds sit 13th in the table with 47 points, having won seven of their last 10 league games.
But Mancienne's Forest side are six points clear in ninth, heralding realistic hopes of an outside shot at the play-off places.