Riva, 79, is the record goal scorer for the Italian national team with 35 goals. He also spearheaded Cagliari’s 1970 scudetto winning team.

Riva was initially reported not to be in a serious condition at Cagliari’s Brotzu Hospital and the heart attack was first described as being minor, accordng to medical sources.

Riva, Cagliari’s honorary president, should make a full recovery after a minor and routine procedure, they said.

Considered to be one of the best players of his generation, as well as one of the greatest strikers of all time, Riva enjoyed a remarkable scoring record for Cagliari, thanks to his composure in front of goal, powerful left foot and aerial ability.

His speed, strength and eye for goal led the great Italian journalist Gianni Brera to nickname him Rombo di Tuono (Roar of Thunder).

At international level, Riva won the 1968 European Championship and was runner-up at the 1970 World Cup behind Pelè’s great Brazil side; he also took part in the 1974 World Cup.

With 35 goals in 42 appearances in official competitions between 1965 and 1974, he is Italy’s all-time leading goal scorer.

After retiring in 1976, Riva briefly served as the president of Cagliari during the 1986-87 season, and was later a senior managing official, player advisor and kitman for the national side from 1988 until 2013.

Former Italy and Cagliari keeper Enrico Albertosi told Sky Sports Italia that he and the Italy legend had spent so many years together, including the scudetto win and the World Cup in 1970, claiming he had “lost a brother”.

“I lose a brother, we spent many years together, we [were roommates] at Cagliari and with the national team, I lose someone who was important to me,” Albertosi said.

“Even today we spoke on the phone and I heard him well, I didn’t know he had heart problems.”

ANSA