He was part of the Wigan side that knocked City out of the FA Cup last season.
Dunkley started his career at Oxford, and has revealed how his former team should approach the game.
He said: “If you can get to 20 minutes without conceding you think 'we have a foot in the game'.
“At half-time we were saying 'we've gone 45 minutes against a top side' and once you get to 60 minutes you think 'we have to have a go'.
“Once we got the goal it was something to hold on to. Then in the last 15 minutes you start to believe.
“You have to enjoy it, but you also need that mentality that you have a ten or 15 per cent chance of winning."