Luciano Spalletti questioned the character of Inter's players after they were held to a fifth successive draw in Serie A.
The Nerazzurri are now eight games without a league win following Saturday's 1-1 result against a Crotone team managed by Inter legend Walter Zenga.
Eder headed the home side in front after 23 minutes at San Siro but Crotone hit back after the break, Andrea Barberis capitalising on a lucky break to poke home an equaliser.
Spalletti acknowledged Inter are not hitting the same heights they were at the start of the season, but challenged his squad to work their way out of their current malaise as they bid for a top-four finish - and Champions League qualification.
"Clearly a little worry does set in, because we don't see many improvements, even after changes," Spalletti told Mediaset Premium.
"We can't just throw our hats in the air, we must work to find some certainties through daily training that can give us a clear idea how to progress.
"Evidently, there are some difficulties, because after all this time we've not won a game and can't play in fluid fashion either.
"We have all dipped a little in form in many different ways. The equaliser was a lucky ricochet, but in attack we are not precise or determined enough to win individual duels or push through a move. We're below-par in more or less every area.
"A few of the players who can make the difference and give that extra quality are a little below par. At the end of the day, it depends on what we do on a daily basis and every day we do well in training, but during the match situation we lack the confidence to get the result.
"Once something goes wrong, we lose confidence and seem to have a weak character. We return to having the fears of what was in the past. There is no other path, we have to approach it logically and try to add something more that can set a clearer objective for us to aim at."
