"It's not really his job to replace Cavani and Neymar, and he can't do all three things at the same time", said Tuchel.
"We can't just place all of the burden and pressure on him". He has to be free to play his game, top play with confidence.
'He has wonderful qualities, he can do a lot of things, extremely strong, with the ball at his feet, he's very good and very strong in challenges and one on ones, taking people on he's always capable of making a difference and I think in my opinion he's always unsafe offensively with Martial, they're a very risky pairing.
"He needs to be positive and realise that it is part of his development".
The 31-year-old made a total of 260 Premier League appearances across a decade in England, scoring 37 times.
"I want us to play with courage, play as a team, together, tight knit, fight, ready to suffer".
"Things are completely different [at United]".
"I always said let's not talk about Manchester United in December and January, let's talk about them in February when the game is coming and the game is now".
PSG recovered from a loss away at Liverpool and a draw at home to Napoli to finish top of their group before being drawn against United in the last 16.
'With the confidence they have at the moment, and how they play, I think United are favourites, ' Fellaini said.
"We miss two key attacking players, but to change our identity for that?.I don't know if it's the moment". "He is an incredible player, wonderful qualities". He is extremely strong with the ball at his feet.
Gianluigi Buffon will rightly go down as one of the greatest goalkeepers of all time when he eventually hangs up his gloves, but he has been embroiled in a battle for PSG's number one spot with Alphonse Areola all season whereas David de Gea now looks to be back at his world-class best for United.