The Nerazzurri were held to a 2-2 draw in Turin on Saturday and they are currently seven points adrift of third-placed Roma, who host Sassuolo in the late kick off on Sunday, and eight behind Napoli.
Pioli feels qualifying for next season's Champions League now appears unlikely for Inter, but he insists they will keep fighting for a top-three finish.
He told Premium Sport: "The Champions League - and an incredible goal we set ourselves - is certainly more distant now.
"We are not satisfied. The performance [at Torino] was not the best, even if the will and desire was there. We missed an opportunity.
"We played against an aggressive opponent, but we did not adapt quickly enough. We made a lot of technical errors.
"There is regret, because in the end we had three or four chances and we deserved to win."