Tottenham should have been awarded a penalty after 35 seconds when Nesta handled in the box. It was very clearly a deliberate handball, and was sufficiently cynical to warrant a yellow card. Lannoy had an unobstructed view of the incident, as did the additional assistant. It beggars belief that supposedly top international referees can get a decision like this wrong. Milan had a penalty appeal turned down in the 23rd minute when Ibrahimovic went down on the edge of the box. Lannoy was wrong to say there was no foul; the only question to ask was whether it was on the line and a penalty or just outside the box and a free kick. Again Lannoy had a good view and reached the wrong decision.
If things were going badly in the first half, they got even worse in the second. Flamini should have seen a straight red in the 54th minute for a ridiculous two-footed, off-the-ground challenge, but escaped with only a yellow. From here on in the match was a fractious and tense affair and Lannoy was just too weak to show cards and get on top of the situation. He needed to show at least one red card to show he was in command, he didin't and the match became very messy.
Flamini was very lucky. He escaped a straight red, and instead got a yellow. Then in the 70th minute he committed another reckless tackle and should have been shown a second yellow and a very deserved red. Likewise Gattuso who pushed the Tottenham assistant coach, pushed Peter Crouch, committed two reckless challenges and showed very obvious dissent to Lannoy at least three times. That's seven cautionable offences, and yet he only got one yellow card. Yepes was correctly booked for fouling Gomes as he tried to release the ball, but Lannoy should have shown him a second yellow immediately for the extraordinary level of dissent he showed in sprinting off down the pitch.
One significant decision that was correct, however, was to disallow the Milan goal in the 94th minute. Ibrahimovic clearly fouled Dawson before knocking the ball into the net, and the nearside assistant helped Lannoy out by raising the flag and signalling the foul.
Apart from poor match control, Lannoy also had a very poor understanding of the advantage rule. However, his fitness and positioning were superb. I cannot understand how he got so many decisions wrong when he was in the perfect position to make them with clear and unobstructed views of all the big incidents.