Because the fear of failure, or nervousness, is what drives winning teams/personalities on. He is not saying he is scared of Portsmouth, but that the fear of failing there would have a negative impact on confidence. The other side of that being that if we win, the boost to the players, knowing they have won at a tricky ground, are top of the league and have 2 relatively easy fixtures coming up could be immeasurable come the end of the season. I agree, I am nervous too, too many false dawns league wise, recently. I would be ecstatic to go there and win 1-0.