Marcus Rashford, Marco Asensio and Donyell Malen struck the goals for Villa on the night.
Hurzeler said, "I think the first goal changed the momentum of the game for sure. The VAR was involved in a lot of incidents. The decisions were right but of course it breaks the the rhythm of the game, kills momentum and then makes it difficult for the players to readjust.
"The small margins made a big difference. For their first goal we had a corner and they score from it on the counter-attack. I think we created enough chance in the first half to win this game, so there were positive things.
"We defended quite well and were well organised and if we had scored the first goal we might sit here with a completely different mood.
"So a lot of frustrations and therefore we have to analyse it and we have a chance on Saturday against Crystal Palace to respond. We need to improve on the small things, that is the main thing."