You can read that in this match there was just one yellow card, in the first half, for a Lazio player. This was a very controversial decision by the English referee. In fact, after the foul, he gave the card not immediately, but it took several minutes. This was a problem (maybe) for him, because he didn't recognize the effective player. He booked Libor Kozak. Then, at the beginning of second half, the card was corrected and he gave it to the right player (Lulic). Ok, it can happen, but in my mind, this was like an attempt to make difficult an easy match. I think it was a clear game without any need of cards, but I have also to admit that it's easy to speak after and not before.
The first goal, that was important to unlock the score in favor of Lazio, maybe was offside. I can't be sure, but watching the replay, Kozak seems in a offside position. However, there were also other calls before, in the first minutes of the match: unfortunately, two mistakes by the same assistant, mr. Stuart Butt, at 2' and 6'. He raised the flag against Lazio both times, and both times he was wrong. Not a so good day for the English team.
As I said, the match was really fair and the players respected every decision. Foul detection was quite good, he whistled without problems, but for the reasons that you can read above, the performance was not so excellent,