Jose Mourinho has led the tributes to Benfica and Portugal legend Eusebio after the 71-year-old died on Sunday morning.
Eusebio, regarded as one of football's greatest players, had suffered from heart problems for several years.
He was top scorer in the 1966 World Cup and the 'Black Panther' scored 41 goals in 64 appearances for Portugal.
Chelsea boss Mourinho said of his fellow Portuguese: "He was one of the great figures of Portugal. I think he is immortal. We all know what he meant for football and especially for Portuguese football.
"He was not only a great inspiration but also an important figure in upholding the values, principles and feelings of football, even after finishing his career."
There was a minute's silence before Manchester United's match with Swansea on Sunday. Before the match Sir Bobby Charlton said: "Without doubt, Eusebio was one of the finest players I ever had the privilege to play against.
"His goals record, for Benfica and overall, is incredible and stands the test of time. I met him on numerous occasions after our playing careers had finished and he always represented both his club and his country in exemplary fashion."
Cristiano Ronaldo, the current Portugal captain, wrote on Facebook: "Always eternal Eusebio, rest in peace."
FIFA president Sepp Blatter said: "Football has lost a legend. But Eusebio's place among the greats will never be taken away. Eusebio was a football and FIFA ambassador. He'll be sorely missed. Rest in peace Black Panther."
UEFA president Michel Platini said: "Today football has lost one of the greatest players ever. On the field, Eusebio was a true legend, both in the colours of Portugal and Benfica. But also off it, he was a true ambassador for Portuguese football on the international stage. He was more than a footballer. A good and charming man, Eusebio will be sadly missed."
German great Franz Beckenbauer tweeted: "One of the greatest football players ever has passed away. My friend Eusebio died last night. My thoughts are with his family."
Former England keeper Gordon Banks said: "He was a great, great player...he could hit it with the inside of his foot, the outside. It made me quite pessimistic when he was taking free kicks."
"He was a gentleman. A real nice guy and he shook my hand after the World Cup semi-final and wished us all the best."
Luis Figo, who retired in 2009 with a national record of 127 caps to his name, tweeted: "The king! Great loss for all of us! The greatest!"
A spokesman for Benfica said: "We will remember his talent, his example, his character which marked Portuguese football and which established him as a global benchmark for football.
"Eusebio's life is the heritage of all those who love football. Benfica was his home port. He made Benfica more than a club, he made it his home and his family. The memory and legacy of Eusebio will remain among us."
Former Manchester United goalkeeper Alex Stepney was involved in one of the most notable moments of Eusebio's career when he made a save from the forward towards the end of the 1968 European Cup final against Benfica that proved pivotal to the outcome.
Eusebio stood and applauded the United keeper in an extraordinary show of sportsmanship at Wembley after his stunning save prevented Benfica taking a late lead, before the English champions went on to win 4-1 in extra-time.
"It wasn't like I got a clear view of what he did at the time," Stepney said. "There was not long left in the game and I was fully focused on it.
"I made the save and out of the corner of my eye I saw him still standing in front of me. It was only afterwards that I saw what he had done.
"The fact he was standing there clapping before running away is a mark of the man. He respected anything we did - and I would like to think it was the same the other way round."
Chelsea forward Fernando Torres wrote: "RIP Eusebio. One of the all time greatest," while Ruud Gullit said: "A great footballer left us and I want to say thanks to Eusebio for all his greatness and beautiful football moments he gave us."
Former Manchester United goalkeeper Peter Schmeichel praised the work Eusebio had done for the sport since hanging up his boots, writing on Twitter: "Sad news that Eusebio has passed away, he was a true legend, a fantastic ambassador to football, a gentleman to the core. R.I.P. Sir."
Toni, who played with Eusebio for both Benfica and Portugal, said: "I told him when he was alive much of what I felt. That it was a privilege to have played with him. We have lost one of the greatest figures of Portuguese sport.
"There were many princes in football but few kings. He is in the gallery of the greats. He was gifted both physically and technically. He was like a Greek statue."
Mozambique president Armando Gebuza said: "He's a figure who has contributed to the deep and rich history of Mozambique. Eusebio came here from time to time. He always maintained a link with Mozambique. He's a very well known and respected figure in our country."