Tuchel claims he didn't even have time to study his opponents before Solskjaer was installed as interim manager – but has been impressed by the Norwegian's stunning start in the job, winning 10 of 11 games in charge.
“I'm not sure it's on me to explain what's changed," he said. “I don't know him or the situation.
"There is an effect and we have a saying in Germany, 'If you go to the doctor and he heals you, he's right.
“If he wins the game, he is right and he wins a lot of games.
“He was super dangerous as a player whenever on the field and it is the same as a manager.
“Things are completely different. They play with a lot of confidence, score a lot of goals, get a lot of early leads.
“It's an impressive run and to play in this moment in Old Trafford, against this Man United is one of the toughest challenges you can have.
“We were in an extremely good shape when we ended the group stage, then there was the draw and things have completely changed. I said let's talk about it in February and it's going to be a tough challenge because the squad is full of energy.
“Over 180 mins it's a 50-50 game. If it's tomorrow, the home side, I'm not sure."