Everton won 2-0 in the first competitive game at their new stadium thanks to goals from Illiman Ndiaye and James Garner.
But Hurzeler said, "Overall we were the better team, but football is about scoring goals and keeping clean sheets. In the final action, the small details, we weren’t at our highest level.
“We created so many big chances. We started well, Everton scored out of nowhere and then we hit the post and had a big chance before half-time. If we score the dynamic of the game is completely different but the result doesn’t lie. Scoring and defending our own goal – we have to do that better.
“(The missed chances) wasn’t down to not having early season sharpness. We had similar situations in the last game against Fulham. We have to work on being more ruthless.
"It’s not always about creating chances, it’s about the mindset of defending together and in some moments we didn’t do it well enough – from re-starts and throw-ins, we weren’t alive in these moments. These are things we have to focus on fixing quickly, which we can do."