Portuguese football legend Eusebio, who was the top scorer in the 1966 World Cup, has died Sunday at the age of 71, his former club Benfica confirmed.
The Mozambican-born Eusebio died of cardio-pulmonary arrest at 0430 GMT, the club said.
Eusebio, the 1965 European Footballer of the Year, is considered one of the best footballers of all time and best ever from Portugal.
During his career with Benfica the Lisbon side won the European Cup in 1962. He scored 733 times in 745 professional matches.
Nicknamed the 'Black Panther', he also helped Portugal take third place in the 1966 World Cup, where he was top scorer with nine goals.
He won 10 league titles and five Portuguese cups in his 15 years at Benfica and was Portugal's top league scorer between 1964 and 1973.
'Black Panther' who lit up 1966 World Cup
Known as the "Black Panther" or simply "The King", football legend Eusebio, who has died aged 71, reigned over Portuguese football in the 1960s, bringing glory to both his club Benfica and his country.
The top scorer in the 1966 World Cup and considered one of the best footballers of all time, Eusebio da Silva Ferreira died of cardio-pulmonary arrest early on Sunday morning.
His death lead to an outpouring of tributes with the Portuguese government decreeing three days of national mourning, with flags in Lisbon to fly at half mast.
"Football has lost a legend," FIFA president Sepp Blatter wrote on Twitter. "But Eusebio's place among the greats will never be taken away."
The top Portuguese footballer of all time Eusebio rivalled all-time greats including Brazilian Pele, Argentina's Alfredo Di Stefano and England's Bobby Charlton.
"I was the best player in the world, top scorer in the world and Europe. I did everything, except win a World Cup," Eusebio said in a interview in 2011, recalling his tears after Portugal's loss in the 1966 World Cup semi-final to England.
From humble origins in the former Portuguese colony of Mozambique, Eusebio da Silva Ferreira was to emerge as one of the World Cup's most feared strikers, combining panther-like pace with a ferocious shooting ability.
Known throughout his career simply as Eusebio, the poor boy from Maputo became a legend for his exploits with Portugal and Lisbon giants Benfica during the 1960s.
Born in 1942, he rose to prominence in Mozambique football circles as a teenager through his performances for Sporting Lourenco Marques, a team with links to Sporting Lisbon.
With his exceptional technique, strength and goal-scoring record, it was not long before word of Eusebio's prowess soon filtered back to Portugal. In December 1960 he was offered trials with Sporting.
Although keen, Eusebio was not willing to risk leaving his beloved mother unless there was the firm promise of a contract. Sporting baulked, creating an opening for Benfica, who snapped up the youngster's signature.
A wrangle with Sporting Lourenco Marques over Eusebio's registration was finally settled, and in 1961 he made his debut for the club, scoring a hat-trick in a friendly.
Over the next five years, Eusebio developed as one of world football's best players.
In an early game for Benfica, he had outshone Pele in a friendly with Santos, and in 1962 he scored the crucial goals in a 5-3 victory over Real Madrid in the European Cup final.
When Madrid's legendary Hungarian Ferenc Puskas symbolically handed his jersey to Eusebio after the match, the message was clear - the torch had passed, and in 1965 Eusebio was named European Player of the Year.
1966 World Cup exploits
But while Eusebio excelled with Benfica in Europe, it was his exploits at the 1966 World Cup for which he will be best remembered.
Eusebio's nine goals in England propelled Portugal to a third-place finish, and a succession of opposing teams simply had no answer to the power and pace of his play.
He scored twice in the 3-1 victory which sent holders Brazil out of the competition.
In the quarter-finals Eusebio was unstoppable, pulling off a one-man rescue act after Portugal went 3-0 down against North Korea after just 20 minutes.
The Koreans were blown away by a four-goal display from Eusebio as the Portuguese won 5-3.
In the semi-final against England Eusebio was effectively marked out of the match but he did find the net again. He scored his ninth of the tournament in the third-place play-off win over the Soviet Union.
He finished his 64-cap career having accumulated 41 goals for Portugal. He also earned European football's Golden Boot award twice and was Portugal's top scorer every season between 1964 and 1973.
He helped Benfica to 11 league championships and five domestic cups. He also appeared on the losing side in the European Cup finals of 1963 and 1968.
In 1975 he joined the flow of players involved in the ill-fated North American Soccer League, before retiring in 1979 after winding down his career in Mexico and Portugal.
Married with two daughters, in retirement he became an ambassador for Benfica and the Portuguese football federation. Always present at major events, he rubbed shoulders with current stars, among them the young Cristiano Ronaldo, now the Portugal captain, and the only one who could one day dethrone "The King".
"Eusebio will always be eternal. Rest in peace," wrote Ronaldo, in a message posted on Facebook alongside a photo of himself and his hero Eusebio.