Kepa has been boosted by Tuchel’s arrival last month, in place of Frank Lampard – who had been deeply sceptical about the Spaniard.
But Mendy is expected to return for Saturday's visit to Southampton, as well as for Tuesday’s Champions League clash with Atletico Madrid.
And Tuchel said: “I encouraged Kepa to take it as a fresh start and to see the possibilities in it.
“That is what he did. He earned his right to play – he had two clean sheets, that is the best a goalkeeper can have for his confidence.
“But nothing has changed. Edouard is still the No 1, he deserves to be the No 1.
“You need to be clear, you cannot hide your opinion in press conferences and in the dressing-room.
“But we need everybody ready, because the goals are high at this club.”
This article was most recently revised and updated 2 years ago