Portugal wonderkid Renato Sanches did snub Manchester United to join Bayern Munich, according to international team-mate Nani.
Sanches, 18, was outstanding in Portugal's win over Poland on Thursday as he scored a first-half equaliser before netting in the penalty shoot-out.
Bayern Munich completed a deal in May for the Portuguese midfielder, who moved to the German champions for an initial fee of £27.5m (35m euros).
United scouted the player extensively during the season but Sky sources indicated Ed Woodward's hesitancy to strike a deal cost the club the player.
Former United player Nani is convinced the player could have become a star at Old Trafford and believes it is a missed opportunity the club will regret.
He said: "Renato would have been a great signing for Man United. I have no doubts.
"But he had a choice - and the choice he made was Bayern Munich.
"I hope he has made a good choice and that he is happy in his career, but I think United will now know what a big player they have missed.
"Renato is a very confident player. He is very young, but he already has a great personality for the game. He isn't scared to play in the big games and he isn't scared to show his qualities against any opponent.
"It is good to see another young player want to be a star and to achieve his dreams. You must be like that. You can't be afraid of anything - and he isn't."
Nani has been in fine form at Euro 2016, scoring twice and supplying two assists during Portugal's march to the semi-finals.
The 29-year-old, who currently plays for Turkish side Fenerbahce, enjoyed good success during his eight seasons as a United player, as he helped the club win four league titles and one Champions League.
He admits he still regards the Premier League fondly and would be open to a move back to England in the future.
"I like England, I like the football, and you never know what the future will bring," said Nani. "One day you could be here, the next you're over there, so let's see."