Mbappe scored on the hour mark against Morocco having earlier had a penalty saved and Ousmane Dembele completed the job as France reached the last four of a World Cup for the third tournament in a row.
"When it's Kylian, there's no problem - he never doubts himself, even though he had another chance before scoring," Deschamps said.
"I think that is three consecutive semi-finals, so that's already a good thing," he added.
"It seems logical and natural, but you still have to achieve it.
"Obviously, I have great players, otherwise we wouldn't get there, but it's good. It was complicated because today, after missing the penalty, and with the chances (we had), we didn't convert."
France will face either Spain or Belgium for a place in the World Cup final.
"It's great; we're where we wanted to be, so we'll recover well and then we'll see who our opponent is tomorrow," Deschamps said.
He added Mbappe had been substituted because he had taken a knock to the ankle - the forward was seen icing this area on the sidelines.