The Cumbrians got off to a dream start in Tuesday night's tie at Brunton Park when Ian Harte stepped up to slot home a second-minute penalty.
But Pompey booked their place in the fourth round of the competition after goals from Aruna Dindane, Danny Webber and Anthony Vanden Borre.
Abbott said: "I think defensively they look like they might have problems, although I don't think that was their first-choice back four. But certainly going forward they seem to have a lot of options and a lot of attacking ideas.
"I think if they can be collective and stay together and defend well, keeping as many clean sheets as possible - and Paul will work on that, then they have a chance.
"We wish them all the best. They didn't come here with any arrogance or attitude. They have come here as a Premier League side off the back of a bad run and done a very, very professional job. Good luck to them."