Antonio Conte said "maybe I was too trusting" as the Inter head coach hit out at the club's management over the planning of his squad following Tuesday's Champions League defeat.
Inter surrendered a 2-0 half-time lead as they lost 3-2 away to Borussia Dortmund, prompting a post-match outburst from Conte.
Goals from Lautaro Martinez and Matias Vecino were cancelled out in a stunning second half, which saw Achraf Hakimi's brace and Julian Brandt lead Dortmund to a Group F victory.
Conte turned his anger on the Inter board following the game, the Italian accusing the Serie A club of failing to plan sufficiently for the season ahead during his interview with Sky Sport Italia.
And former Chelsea boss Conte continued his outburst in his news conference after Inter were left third and three points behind Dortmund in the race for the Champions League knockout round.
"I had my part into the planning together with the team officials, so... I've always said this and I reiterate it here," said Conte, whose side signed club-record recruit Romelu Lukaku, Alexis Sanchez, Stefano Sensi, Nicolo Barella, Diego Godin and Valentino Lazaro for the 2019-20 campaign.
"Maybe I was too trusting in some situation, that's true. I was too trusting in some situations when I shouldn't have been so trusting. But it is what it is."
Conte, whose Inter are a point adrift of Juventus in Serie A, added: "It feels like I always have to repeat the same things. I said that I am worried, I said 'I am worried' when we were winning. I repeat, I can't pretend anything more from these guys, I can't say anything to them.
"That said, there's a lot to work in order to improve and to learn how to manage every moment, especially when you are tired mentally and physically, if we want to make a step forward.
"But at the same time I am well aware that there are things I can't pretend from my players because some of them could rightly tell me 'mister, I am playing every single match from the first to the last minute.' Therefore I have nothing but respect for my players for what they are giving me."
While Conte was frustrated afterwards, Lucien Favre and Dortmund were delighted as they moved second on matchday four – a point adrift of leaders Barcelona in Group F.
"They [Inter] were very dangerous and we played very offensively because we really wanted to win the game," Dortmund coach Favre said. "We took a very high risk. We were often in the defense in two against two situations. And we made some corrections in the half-time break. We stayed very positive. Everything was still possible because our first half was absolutely not bad.
"Of course it was a crazy game in the second half. We played a lot forward and pressed well. We had more ball possession. And we played with patience, intensity and speed. It was a nice game."