Ninth-placed Pompey host Birmingham in the Premier League on Tuesday as part of a pack of clubs that have been eyeing a UEFA Cup spot all season.
He said: "The way it has panned out looks to me as though there will only be five European spots from the league so whoever wins the cup will get the last one - unless it's Cardiff of course as they can't qualify.
"And if you are honest you would have to say that Liverpool and Everton look odds-on to finish fourth and fifth. They are 12 points ahead of us and that would take some cutting down with 10 games to go.
"The cup is our best route but we still want to finish as high as we can in the league. We want to keep going and keep going."