Manchester United scouted Sporting Club winger Gelson Martins on Thursday - although he only came on as a 63rd-minute substitute.
Reports in Portugal claim United sent a spy to the Portuguese cup match as a weakened Sporting line-up won 1-0 at second division Famalicao.
The Red Devils have been tracking the talented 21-year-old all season and can only have been impressed by his performances in the big games this season - particularly in the Champions League match at Real Madrid.
Martins played less than half an hour of the match on Thursday and didn't write any more headlines for himself in a routine away win.
United, who regularly scout the big three clubs in Portugal, also had a spy at the Under-19 Lisbon derby on Friday as Sporting beat Benfica 2-0.