The R’s and Reading played out a 0-0 draw at the Madejski Stadium, condemning both clubs to the Championship, and Redknapp is well aware just how difficult it will be to return to England’s top flight.
"There's a lot of work to be done next year and it will be very difficult to get promoted," Redknapp told Sky Sports. "There are some good teams in the Championship.
"The first thing I said to them is we have to come back in pre-season and get super fit because the Championship is Saturday-midweek, Saturday-midweek and if you're not fit enough to go the pace, you won't survive and you won't get out of that league.
"That's the key. Whoever the players we have here, they've got to be worked on in pre-season and they've got to be willing to want to get super fit to compete at that level.
"It will be a big challenge. There are lots of good teams and massive clubs. There are big clubs who have all been in the Premier League before and we are just one of them.
"We will do our best next year to try to get up, but we are going to have to work very, very, very hard in the summer, during pre-season and certainly during next season to try to achieve that.
"It's a real good challenge. It's possible but it ain't going to be easy."