Tuchel questioned his side's commitment after they were thumped by the Gunners.
First-half goals from Gabriel Jesus and Martin Odegaard put the Gunners in complete control at the Camping World Stadium and before the second period was over, they were up by four goals.
The new season is just two weeks away and Tuchel was worried after seeing his team collapse against one of their rivals.
He said that they deserved to lose because they were not good enough.
We weren't competitive. The worrying part is the level of commitment, physically and mentally, for this match was not the same as the one we played.
Their strongest line-up has been together for more than a year, and they played with it. They've strengthened their line-up, played the same structure, and this is the line-up they'll try to start games in the premier league
This is part of an explanation, but not the full one. The other part is not good.
The only positive for Tuchel was the debut of Kalidou Koulibaly, his first appearance since signing from Napoli.
The need for the club to make more signings was highlighted by his performance.
Tuchel said there was no update. This game does not affect the analysis of the season.
The last week proved my point. I would rather not be right and I did everything I could to prove myself wrong, but at the moment I think I'm right.
We know that some players are trying to leave and this is where we are. An urgent appeal for quality players and a lot of quality players was made by us. We have two quality players but we are not competitive like this.
Following the departure of Romelu Lukaku to Inter Milan, the club needs an out-and-out forward.
The bigger picture of this defeat means that they are way behind their rivals.
He said that the two teams in front of them should not be mentioned.
We were beaten by a team that doesn't play in the league next year. It appears far ahead of us.
The Blues were beaten on penalties by Charlotte FC after giving up a late goal in their previous pre-season game.
Tuchel wasn't prepared to use the America tour as an explanation of their battering because he didn't want to give away too much.
It wasn't short. He said it was lengthy. It's also hard. The energy level dropped after Las Vegas and after the Charlotte game because of a lot of travel. It was difficult because we are on the road for two weeks.
That's a point, but it's not the only one, it's a small point in the explanation why we didn't look fresh. I did not think it would happen. We lowered the intensity and volume of training over the last few days, but not in a way that we would expect to have fresh legs. That was not the most surprising thing. There is a difference between being tired and playing well.
I don't know if I've lost a match in pre-season by four goals. I can't recall. I haven't won two matches in a row in a long time.
I like a strong pre-season for a number of reasons.
I'm a part of it." I'm involved in it. It's necessary to find solutions. We're going home right now. We only have one and a half days to present solutions. We need to present actions, like we, me, coaching staff, together with our team to stand up and find a way through this, because it hurts right now.
The final pre-season game for the Blues will be against Udinese in Italy on July 29th. The kick-off time is 8pm.
The transfer window will close at 11pm on September 1st.
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