The Hoops lie in 19th place in the table, seven points from safety with seven games remaining, but the midfielder believes that his team have a fighting chance of survival.
"I really don't think we are down. I said the same a couple of weeks ago but I still think there is going to be a twist," he told talkSPORT.
Derry added: "The game against Wigan is an incredible game. I think we have got to win three and draw one out of the next four to be in with a shout. That's how important the next four games are.
"We're running out of games now. As important as it was to get the win against Fulham, it's now paramount we get a win on Sunday."
Wigan go into this weekend's game seven points ahead of QPR in 17th place.