La Dea host Napoli on Wednesday for the second-leg of their Coppa Italia semifinal with the scores locked at 0-0.
“We had almost won the game, it's a bad sign," Gosens said of the Toro result.
“We can't throw victories away if we want to qualify for the Champions League. But it happened and it means something is not working.
“I don't think it depends on tiredness because we are all fit. I think there were different factors, including too many distractions."
He added: "The Coppa Italia offers us the quickest path to win something, it we beat Napoli we'll qualify for the final.
“Serie A and Champions League are longer and more difficult, if we qualify, we'll be aiming to win the Coppa Italia."