The legendary forward, regarded by many as one of the greatest to play the game, has passed away after reportedly suffering a cardiac arrest.
Reports in Portugal indicate that he passed away after suffering a cardiac arrest in the early hours of Sunday morning.
Born in Mozambique in 1942, Eusebio was brought to Portugal by Benfica coach Bela Guttman, who signed the player in 1961 after making a trip to Africa to see him play.
The attacker went on to become a legend for club and country, winning 11 Primeira Liga titles, five domestic cups and the 1962 European Cup with Aguias, as well as inspiring Portugal to third place in the 1966 World Cup.
With his speed, power and skill, Eusebio was an unstoppable force in the Portuguese league and averaged more than a goal a game, hitting 319 in just 313 league appearances, and remains Benfica's all-time leading scorer.
His talent saw him finish top scorer in Portugal six times, twice win the European Golden Boot (1968 and 1973) and be named European Player of the Year in 1965 as Benfica became a powerhouse of European soccer.
He also earned 61 caps and scored 41 times for Portugal, most notably finishing the 1966 World Cup as one of the stars of the tournament. He scored nine times to secure the Golden Boot and also netted as his side overcame the Soviet Union 2-1 to seal third place.
After 15 years at Benfica, Eusebio played out the remainder of his career in North America, representing a number of teams in Mexico and the USA before retiring in 1978.
The former striker is regarded as one of the finest to play the game and placed ninth in FIFA's Player of the Century poll.
Cristiano Ronaldo was among those paying tribute to Eusebio, writing on his Twitter account: "Always eternal, Eusebio, rest in peace."