The 32-year-old has praised the defensive midfielder and insists that he will become a crucial player for club and country
The 24-year-old came through the ranks at Real Sociedad’s youth academy – just as Alonso did years before – and then completed a £34m move to Madrid in the summer of 2013.
Alonso believes the defensive midfielder has done well in his first season with the Spanish giants and is confident he will develop into a key player for club and country.
"Illarra is the future. He is in his first year with a major change. It is important for him. I have no doubt [of his talent],” Alonso told Cadena Cope.
“Madrid is a bull and we must be prepared for this – and Asier is going to be.”
Illarramendi made 29 league appearances for Carlo Ancelotti’s side last season, scoring two goals and making one assist for his colleagues.