Keen played under Redknapp two decades ago at West Ham, when he was number two to Billy Bonds, and is backing him to keep QPR in the Barclays Premier League.
"Harry has installed a new feel into the club. The couple of results they got over Christmas has given them a bit of confidence that wasn't there.
"But I also think they will want to progress in the FA Cup. They've not got European competition, similar to ourselves, so it is not like there are a load of games coming up.
"I've been in clubs where you've been down the bottom and playing in the cup is a refreshing change.
"Players play with more freedom rather than the pressure of relegation. They will come and have a go and certainly we are up for it as well."