Marco Silva has cited Dominic Calvert-Lewin's disallowed goal as the turning point in Everton's 2-6 defeat at the hands of Tottenham on Sunday.
The Toffees had put themselves ahead early on through Theo Walcott and looked to have doubled their lead through Calvert-Lewin, but the goal was ruled out after referee Paul Tierney declared that the forward had pushed Davinson Sanchez in the back before heading the ball home.
"We started well and the second goal is a key moment in the game," Silva told Sky Sports. "The referee saw something there. Then, after that, we made a big, big mistake and gave them a moment to equalise.
"After that moment we have to keep our composure and shape, we have to keep playing in our way and being aggressive, but we kept making mistakes and you can't do that against a team like Tottenham.
"We feel really bad, as we should. We wanted to achieve something different and tried to give our fans different feelings."
The defeat extended Everton's run without a win to five games, but Silva insisted that his side will stick together during their rough spell.
"When something like this happens we have to forget the top six and wins against them. We did so well in previous matches against them but we have to improve and when we play them again we have to be able to compete, nothing more.
"I'm not here to say one or the other. We win together and when we lose and make mistakes we have to be together too.
"Tottenham played faster than us and we have to look and realise why it happened. When we played the first 20 minutes so well before it went 1-1."