Ferguson saw his side take another step towards safety on Saturday with a 2-2 draw at Coventry while the Reds were falling to defeat against Bristol City to re-awaken their own relegation nightmare.
"Forest have been particularly good on their travels so it will be a difficult game," the Posh boss told his club's official website although, with United strong at home, he was confident of the right result.
Steve Cotterill meanwhile felt his men did little wrong against Bristol apart from being unable to put the ball in the net.
Check out the head-to-head records of the two sides by clicking below.
http://www.nottinghamforest-mad.co.uk/head_to_head/next/vs/match/index.shtml