Barcelona coach Xavi has informed his players to watch out for Marcus Rashford on Thursday.
The Catalan giants, who are top of La Liga, take on United in the Europa League.
The two sides will meet for a two-legged round of 32 clash, with Barca dropping down from the Champions League earlier this season.
He's is one of the most dangerous players in Europe, I would fully agree," said Xavi to reporters of Rashford.
He is very fast, a good dribbler one versus one, and dangerous in the transition.
It's not like we are expecting only one player. We have assessed what they do and how quick they are on the transition, with (Alejandro) Garnacho, (Jadon) Sancho and (Wout) Weghorst. The counter strike is very quick. They have strong legs, so we need players who are capable of correcting the fast breaks.
'We need to take care of all of them but, yes, Rashford is one of the most dangerous in Europe."