Basically, the big matches were all played on a setup of two players watching different TV screens which had their backs to each others (so the players could see each other head on) while the audience could see the match on a big projector screen. When we got to this room, one of the previous matches was showing a result of 2-5 (in favour of the right team).
I don't know the exact scores but the first semi final finished 1-3 in favour of the right player. The other semi finish 3-1 in favour of the left player. Then the final took place and it finished 2-3 to the right player.
The winner later said he knows that the game favours players by switching like that and that's why he sat on that side. It was a very close match and I believe that if the other finalist had sat on that side, he would have won the match, and by a bigger margin. You can see this effect happen even on the PS2 version if you keep playing matches between two players. One match will be quite easy for you and the next one will be much harder, with your players making bad passes and giving away possession easily. Goalkeepers also seem to be affected by this strange effect. Anyways. Try it and see. If you play someone of a similar standard, it will be possible to see a pattern like this.
Summary: the game is a little down to luck of which player you are, rather than how you play the game. Which is a big shame and another reason why PES08 (and a few of the previous versions) have been so poor in comparison to the good days of PES3 and PES4.