After Harry Kane had given England the lead, Senegal took control to win 1-3 through goals from Ismaila Sarr, Habib Diarra and Cheikh Sabaly.
It marks the first time an African nation has beaten England at senior level.
Tuchel insisted afterwards: "Yeah of course, it's a disappointing result. Not sure if we did not deserve a little bit more result-wise. Felt a bit frozen, not active enough for a long time over the match. We defended quite well for long periods in the first half and then our best period came when we were 2-1 down. We conceded the first two goals - very easy goals, we need to defend better.
"The reaction was good after we were down. We suddenly were more active, more free, more fluent, more aggressive. We had big chances to equalise."
On the disallowed goal: "I just saw it, it looks more the shoulder than the hand. I saw it as a goal needs to be checked, it is the first time the referee revisits a goal. So either it is a mistake, so take it away. Or it's not a mistake, so it's a goal."
On bringing Ivan Toney on late, Tuchel added: "It was more than three minutes. I think Ivan is a specialist for these situations, we created a lot of chances with Morgan Gibbs-White, Ebs (Eberechi Eze), Morgan Rogers and with Jude (Bellingham) in fluid positions. I think Ivan is the strongest when we have a lot of balls into the box, and that was the case so we got him ready at 80 minutes."