Sunderland have completed the signing of Greek winger Charis Mavrias from Panathinaikos for an undisclosed fee.
Sunderland's summer signings
- Jozy Altidore
(AZ Alkmaar) Undisclosed
- El Hadji Ba
(Le Havre) Free
- Ondrej Celustka
- Modibo Diakite
- Emanuele Giaccherini
- David Moberg Karlsson
- Vito Mannone
- Valentin Roberge
- Duncan Watmore
- Charis Mavrias
The 19-year-old Greece international has agreed a three-year deal with the Black Cats.
Mavrias made his Champions League debut as a 16-year-old in 2010, becoming the second-youngest player ever to figure in the competition.
The teenager has made 59 domestic and 11 European appearances for Panathinaikos, scoring six goals.
He has also made two appearances for Greece, having also appeared at Under-17, Under-19 and Under-21 levels for the national side.
Mavrias, who will wear the number 35 shirt, is
Sunderland's 11th signing of the summer.