Kassai is considered by many the number one of the world, so getting him as your referee of the night must be some sort of a compliment.
There are many good referees in Europe, I don't really know why Kassi is supposed to be better than the rest.
He stands quite far off, but whistles a lot and looks very sure of himself when he does. Unlike Brych who uses his whistle as if it's a tuba, Kassai's whisle is subtle. Kassai is very formal too and never sloppy: after he whistles he always runs to the place where it happened, he waits for a player to get up before he shows him his yellow card.
He whistled a lot in this match, and showed 8 cards! Not all of them necessarily. When Ushida fouled badly, Kassai saw an advantage situation, but forgot to book the Schalke sider later on.
It was clear from the start that there was some animosity between Farfan (Schalke) and Tiendalli (Twente), Farfan is a bit of a nasty character and Tiendalli just wasn't up to it. This had to end with a card or two and it did. A referee can do two things (actually three : he can also not notice it):
1. Think of these two as children so warn them off by talking to them (i.g. Collina)
2. These two are adults and if they want trouble they can have it, it's up to them (Kassai).
And this is what you do as a player with Kassai in charge: whenever you are in a difficult spot and you can't get past your opponent, be sure to lean against him, stumble, pretend to try to stay up by moving your arms in every which way, then fall but take care to fall a moment earlier than the other guy does.
It always works: Kassai whistles and if your lucky he even books the other player.
This must be in every text book on football coaching: don't ever ever start a match thinking you can defend a one-nil by slowing down and keeping the ball with your side. In fact Twente coach McLaren kept two of his best players on the bench.
There was some speculation he did this because he thought the national competition more important and wanted to keep his players fresh for the weekend. Then, at the end of that national competition, teams want to end within the first four so they can play in a European competition the next season. And when they do they spare their players again because it's less important. That makes no sense to me.