It's a strange state of mind. Their success in some way rebukes your judgement, confronts your arguments against them, makes you feel dumb. And yet success it is, for the good of the team.
It depends a little on whether your dislike of the player is rational and reasoned or whether it's personal, whether it hurts. Prejudice is one of the natural states of fandom, after all. I can say with a clear conscience that I enjoyed watching Bell bat in both innings at Newlands. They showed his range as a batsman, and, as most innings do, provoked his weaknesses too. He came through for his team in a meaningful last afternoon's cricket, and it was not just an individual victory - it rather pleasingly reinforced the decision making of captain and coach. And it shoved it up the Saffers, too, of course...
It's notable also how success recasts Bell's efforts in the Ashes. His couple of patchy of fifties, especially the one in the first dig at the Oval, have a different glow; their positives, rather than the negatives, are reinforced.
A note of caution: Bell himself seems to be under the impression [in his interviews at least] that he has repaid the investment in him, a notion Andy Flower went to some lengths to disabuse him of yesterday.