Real Madrid great Alfredo di Stefano is in a serious condition in a Valencia hospital after suffering a heart attack at the age of 79.
Di Stefano helped Real dominate European football in the 1950s
Doctors will decide on Monday if he is strong enough to undergo the heart bypass surgery he needs to recover.
"His heart is beating with difficulty," said a hospital spokesman.
"He has a circulation problem and some arteries feeding the heart have been seriously narrowed. Operating now would be in unfavourable circumstances."
Real board members have travelled to Sagunto near Valencia to visit Di Stefano, who helped Real win five European Cups and eight league titles and was twice European player of the year.
He was born in Argentina and played for his homeland, Colombia and Spain - but never featured in the World Cup finals.
Di Stefano began his career with Argentine giants River Plate in 1945. He then moved to Colombia's Millionarios in 1949, where he won four league titles and scored 267 goals in 292 games.
He joined Real Madrid, after a tug-of-war with rivals Barcelona, in 1953 and was instrumental in their amazing five consecutive European Cup titles from 1956.
Di Stefano scored goals in every final, including a hat-trick in their famous 7-3 victory over Eintracht Frankfurt at Hampden Park in 1960.
He held the record as top scorer in the European Cup, with 49 goals in 58 games, until Real Madrid striker Raul beat his mark this season.
He was voted European Footballer of the Year in 1957 and 1959.
He left Real for Espanyol after falling out with club president Santiago Bernabeu in 1964 and retired three years later, playing his final match against Celtic in Madrid.
He then went into coaching, leading Boca Juniors and River Plate to Argentine championships and steering Valencia to a Spanish league title in 1971 as well as victory over Arsenal in the European Cup Winners' Cup in 1980.
He returned to Real Madrid to take over as coach between 1982 and 1984, with the side finishing runners-up in the title race in consecutive seasons.
Di Stefano was made honorary president of Real in 2000 when Florentino Perez came to power.
Perez, who was among the group from Real that visited Di Stefano, said: "He is fully conscious. We talked about everything.
"He told me one must address life with a bit of philosophy and to me it seemed that his situation, given what he has been through, is normal."