The Bavarians struck twice in four minutes early in the second half with a shot from Leroy Sane and a Harry Kane penalty to turn the game around after Vinicius Jr had put the visitors ahead in the 24th against the run of play.
The Brazilian striker also bagged an equaliser with an 83rd-minute spot kick as Bayern were pushing for a third goal.
"The result is what it is and it's not worth spending any time thinking about it," Tuchel, who will leave Bayern at the end of the season after a disappointing domestic campaign, told a press conference.
"Real have done it before, to score twice with two chances. We are not the first team to suffer that. They have the finish, they have the quality to do that.
"We had a strong start then we lost a bit our rhythm. We should have scored a third but we were not efficient enough, not cold enough to add a third. Then we gifted them a penalty."
Bayern enjoyed a strong start and also had chances to score again after going 2-1 up. They will now need to win against Real, who are chasing a 15th European Cup, in Madrid next Wednesday if they are to advance to the final at Wembley.
Borussia Dortmund and Paris Saint Germain face each other in the other semi-final on Wednesday.
"The situation is now very clear," Tuchel added. "We go to Madrid and the winner takes it all. We are ready to fight. It is important to believe that.
"It is still possible. It is 50-50. It is one of the toughest places to win but that is also what makes this challenge exciting."
