Chelsea were blown away by Mikel Arteta’s Gunners, with goals from Gabriel Jesus, Martin Odegaard, Bukayo Saka and Albert Sambi Lokonga sealing a 4-0 win for Arsenal in Orlando.
Tuchel slammed his Chelsea players after the emphatic defeat and admitted the result was ‘worrying’ ahead of the new season.
But the German boss saw one reason to be positive after Arsenal’s win, with new arrival Koulibaly impressing in a second-half cameo.
The Senegal centre-back, who completed a £33m move from Napoli last week, came on for the final 20 minutes and was ‘incredibly good’, according to Tuchel.
‘He was the best player on the pitch for us,’ Tuchel said. ‘He was incredibly good I have to say.
‘On an evening where nothing felt good, this felt very good.’
Chelsea finished third in the Premier League last season, five points above Arsenal but 19 points behind champions Manchester City.
Liverpool also pulled clear of the Blues and Tuchel says it is pointless to compare Chelsea with the Premier League’s two elite clubs after an underwhelming pre-season.
‘Given our last two weeks, our game today, we should not mention the two teams in front of us,’ Tuchel said.
‘We got absolutely beaten by a team that does not play Champions League football next season and finished behind us. But at the moment, they seem far ahead of us.’
A clearly agitated Tuchel added: ‘I think we deserved to lose – which is fair enough – because we were simply not good enough.
‘We were absolutely not competitive. The worrying part is the level of commitment, physically and mentally, for this match was not the same, it was far higher for Arsenal than us.
‘We can argue they played with I think their strongest line-up; they’ve had now together several weeks and for more than one year.
‘They’ve strengthened their line-up, played the same structure, and this is the line-up they’ll try to start Premier League games.
‘It was not our strongest line-up and this is part of an explanation, but only a little part. The other part is worrying.’
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