Diogo plays alongside Sebastien Leto, who is currently on loan from Liverpool, and Boro sent scout Derek Bragg to watch the two youngsters in the midweek clash with Danish side Nordsjaelland.
Bragg told the Greek press: "Diogo and Leto are very good players,
"Both of them can make it at the Premier League. I watch them and I will keep watching them.
"They have good chances to make a brilliant career in England."
Chelsea, Arsenal and Liverpool are also said to be interested in Diogo and will apparently have scouts watching Olympiakos' up-coming match with AEK Athens on Sunday.




