This story has been reproduced from today's media. It does not necessarily represent the position of Liverpool Football Club.
Liverpool scouts watched Saul Niguez play for Rayo Vallecano against parent club Atletico on Sunday night.
The 19-year-old midfielder played in an unfamiliar centre-back role and scored an own goal in a 4-2 defeat.
Arsenal and Manchester United have also watched Niguez as they consider bids for the Spain U21 man.
Saul comes from a football family. His father, Jose Antonio, was a striker with Elche while his older brothers, Jony and Aaron, are midfielders who played at Valencia but have since moved on to Alocorcon and Elche.
Liverpool held a meeting with Saul's father Jose Antonio last week as he was in England to ascertain how concrete Premier League interest was.
He has a buy-out clause but hopes an offer of £8million can persuade Atletico to sell.
They may also consider it after his display against Diego Costa and the rest of the Madrid attack, who picked Vallecano apart at will.