Redknapp has previously played down their chances of a top four finish.
He said: “We have to believe and we’ve got to have a go.
“That is the aim and I can’t keep saying we can’t. This is the year the top teams are getting beaten.
“Other years it’s been different but Chelsea and Liverpool have been beaten this weekend. Liverpool only lost twice last year in the league.
“There are teams now who, on their better days, can knock the top sides over, so I think the league is getting closer.
“Aston Villa got a great result (against Chelsea) and are going to be there, Manchester City can achieve anything with that squad. We can look to push and be around that top group all season.”
