Celtic are one of a number of European clubs keeping tabs on Atletico Madrid winger Rodrigo Riquelme, according to Marca. The Madrid based publication claims that the Hoops have already “knocked on the door” about signing the teenager, along with Old Firm rivals Rangers.

They are not the only ones involved in the race, however, with German clubs such as Hoffenheim, Dutch sides and English Premier League teams also watching developments.

Riquelme does have a €30m release clause but with his contract expiring in the summer, the 19-year-old could well be available for a nominal fee.

Atletico would like to sign the Spaniard onto a new deal but the player is unhappy with the lack of game time he has been afforded by manager Diego Simeone. He has managed just two substitute appearances in total, one in the league and the other in the Copa del Rey.

His most notable performance of the season actually came against Rangers’ Under 19s in the UEFA Youth League, contributing a hat-trick of assists in a 4-0 win back in February.