I think it was very dissapointing to see him say those words. He knew it was wrong, it wasnt an off the cuff remark, as you can see him covering his mouth and trying to hide it from view.
You talk about pressure and high intensity but you have to be of a prejudiced disposition to think of saying such things. Many other footballers are in high pressure matches and don't say such things. I don't buy the high pressure argument for one minute, every day policemen, doctors, judges etc have to deal with high pressure situations, but it wouldnt for a moment excuse them from displaying such racism.
You can talk about diving, crowding the refs, or the personal animosity between the coaches, all of these are bad, but in my opinion to have a player calling another player "monkey" because of his skin is disgusting. For a player to this in the semi final of the biggest club competition in Europe, while playing for a team that labels itself as "more than a club" sends out a very bad image of football.