Apart from the missed handball (see paragraph below), it was a good first half. He had a clear line for free kicks and always a good view for duels. Both assistant referees were good, too. In minute 7, when the goal was scored, there were two Dortmund attackers who influenced the view of the goalkeeper, it could have been offside, but they were on level, rather onside than offside, very close but well seen by Nikolay Golubev. In the second half, the tension increased and he cautioned some players mostly for tactical fouls..no mistake in his card policy, there was a difficult situation to solve when Lewandowski targeted the goal and fell over a defender who had fallen on the ground before, if he whistles, he must send off the Greek with a second yellow card, perhaps even straight red, but it was rather a foul committed by the striker than by the defender, well seen. His body language and communication with the players was not very good, he could have sent off Perisic who committed a brutal foul and then got excited and tried to kick the advertising boards but slipped...there have already been referees in Bundesliga who issued a double yellow -> red card for such situations..but ok.
I agree with him on the first penalty situation. There was probably a small contact but the Greek (although there is only one Greek in Piraeus' team) fell too late and too obvious..but the second situation. After a corner kick, goalkeeper Weidenfeller was attacked in the 5m-box, then Hummels (BVB) clear touched the ball with his hand. It must be either a penalty or a free kick for Dortmund, he gave goal kick, then protests came up, he had eye contact with ADD-ASS-REF Eskov, then he suddenly decided on striker-foul on Weidenfeller. Replays showed that it was no foul on the German goalkeeper which means that he should have whistled a penalty to Olympiacos in the first half, of course a match influencing mistake, even though there is some kind of justice after Bas Nijhuis had missed a clear penalty to Dortmund when Olympiacos led with 1-0 in the first leg two weeks ago.
Uilenberg refereed some matches in Dortmund himself and he actually should know the atmosphere. Considering the situation in group F and the atmosphere apparent in Dortmund, it was to my mind not the best choice for this match.