Senegal made history Tuesday night, becoming the first African country to beat England.
They came from behind to beat England 3-1 in an international friendly.
The hosts took the lead early through Captain Harry Kane.
But the Senegalese fought back to dominate the match played at the City Ground.
Ismaila Sarr made it 1-1 before Habib Diarra burst through to give the West Africans the lead.
England were sluggish about taking a free kick and it led to a counterattack, which saw Cheikh Sabaly put the game out of reach.
This is also Tuchel's first defeat in charge of England.
Before the game, the Three Lions had recorded a narrow 1-0 win over Andorra.
Thomas Tuchel had been critical of his team's performance and demanded better against the Teranga Lions.
Reacting to the loss, Tuchel said his side lost to the visitors because his team conceded very two easy goals.
While describing the result as disappointing, he said: "Yeah of course, it is a disappointing result.
"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."