Watch: Thomas Tuchel frustrated as Chelsea falter
Mislav Orsic’s 13th minute strike was the only goal of the game at Stadion Maksimir with the west Londoners failing to reach anywhere close to their highest level.
Speaking to the media after the match, Tuchel admitted that he didn’t see such an upset coming against the Group E minnows, putting the Blues under early pressure in their Champions League campaign.
[I’m angry at myself] because I didn’t see it coming," Tuchel said in Croatia on Tuesday night. "Obviously I was in the wrong movie. I did not see that coming.
"I thought that the last game helped us, I thought we showed a reaction in a very difficult moment against West Ham, got the reaction, got the result in the moments when you need a bit of luck in the situation we were in.
"We had good training sessions, I thought the team was prepared, I thought we know what this is all about. I didn’t see it coming, that’s why I’m angry on myself."
Tuchel added: "I’m angry with myself and I’m angry with our performance. This is a huge underperformance from all of us. It’s not precise enough, it’s not clinical enough, it’s not aggressive enough. It’s not determined enough and not enough individually and not enough as a team and that’s why we lose this game.
"It’s for me to find the solution and find the reason why. Obviously they are underperforming individually and I don’t really know where this performance today comes from.
"A lack of determination, a lack of hunger and a lack of intensity to actually do the things that we need at the highest level. We are clearly not where we want to be.
"We had an amount of deliveries and an amount of spaces and an amount of ball wins that should be by far enough to have far more attempts but we did not. We conceded a goal with two players in a counter attack [which] never happened before.
"I don’t understand why it happened today. It’s clearly my job to analyse it so this is my analysing from the sideline and it will continue. We need to be much better. We are not finished, we are not happy with our results, we are not happy with the way we play in general, but I thought we were in a good way.
"I’m a bit surprised by this performance today. There is no day off. There is no day off in the planning and there cannot be a day off in the moment."
The Blues have endured several bad performances already this season, losing to both Leeds and Southampton.
After the 2-1 defeat to Ralph Hassenhutl’s side, Tuchel said his side were “soft” and challenged them to toughen up.
Tuchel denies that his words have had a negative effect on the dressing room, with only Mason Mount stepping up to speak to the TV companies after the final whistle.
"It’s a bit of a game you play when you say I was so super critical," he continued. "I said we need to toughen up in set pieces and in challenges. This, for me, is not super critical. You ask me a question and I give you an answer.
"It depends a little bit what you make of it. I don’t think you lose a player. If you lose with Chelsea against Southampton in the way that we lost with a set piece with a goal against seven eight nine players in defence, of course you need to toughen up.
"It is simply a reality. I don’t see that this is a big issue. I think that I use the word we a lot and this word includes me, so I don’t see a point where I lose the team and I answer your questions."