After consecutive matches against Manchester United, Chelsea, Arsenal and Liverpool, Pompey now face a trip to in-form Blackburn Rovers on Sunday.
Mark Hughes' team stretched their unbeaten run to 15 matches with a goalless draw at Chelsea last weekend and Redknapp insisted: "Some people seem to have overlooked Blackburn when they talked about our tough start.
"It's another easy one for us, isn't it? I don't think so. Mark has done a good job at Blackburn and it is one of the last places you want to go. There are no easy matches at this level and this one certainly isn't.
"Blackburn have terrific players and a way of playing that is very difficult to combat.
"They have people with a lot of physical presence but also a lot of skill. Their record speaks for itself."