The two teams haven't met in the Premier League for 16 years.
Bielsa was asked about facing Sir Alex Ferguson's United while in charge of Athletic Bilbao: "I have noted down a memory with respect to that game against Man Utd. Anything I say about Ferguson is just to confirm everything he has already done. Of course, what Ferguson means to all his colleagues.
"I have noted anyone in the presence of Ferguson is like receiving a medal. In relation to the game we played, he had a praise I never forgot. He said he wasn't surprised Athletic had won, that it was within what was possible and he also wasn't surprised how much the team had run to be on equal terms with them.
"What did surprise him was on the day of the game, in the morning, my team had trained an hour and a half on the morning of that game. I never forgot that comment from him. There's sometimes training on the day of the game is an exaggeration, for some.
"There is something that justifies training on the day of the game. Of course, the training consumes some energy necessary in the night. They are training sessions advise them of co-ordinations needed in the night of the game. They permit you to run less in the game because you are running in the correct manner.
"It's difficult to explain a training necessary on the day of the game, but the justification was it was needed for the team to run in a co-ordinated manner and, therefore, less. As we all know, any explanation of this needs to be validated by a victory."