United are looking to reach the Europa League quarter finals but first have to get past Bilbao, starting with a first leg tie at Old Trafford.
Sir Alex will be taking nothing for granted though as he admits that this the best Bilbao team put together in a long time, a sentiment echoed in Spain and Europe.
Currently sitting a point off a Champions League place in La Liga, Bielsa has been credited with turning Bilbao’s fortunes around and Sir Alex has hailed his opponent ahead of tonight’s game:
“I admire his work because I see the emergence of a very good Bilbao side.
“They are very determined and organised, with a great belief in themselves. That is the hallmark of their coach. He has instilled these qualities in his team.
“We know how difficult a game it is going to be for us. This is the best Athletic team I have seen for some years.”