With fans worldwide on edge over his health, ailing 82-year-old football legend Pele wished the Brazilian national team luck Monday for their World Cup last-16 match, saying he would be cheering them on from hospital.

Considered by many the greatest footballer of all time, Pele was hospitalized in Sao Paulo last Tuesday amid ongoing treatment for colon cancer, just as Brazil wage their campaign to win a record-extending sixth World Cup in Qatar.

"I'll watch the game from here at the hospital and I'll be rooting for each one of you," Pele, the only player to win three World Cups (1958, 1962 and 1970), told the "Selecao" on Instagram as they prepared to take the pitch against South Korea in Doha.

"The King" posted a faded color picture of himself as a baby-faced 17-year-old in Stockholm, Sweden, looking dapper in a sweater and slacks on his way to dazzling the planet with his extraordinary talent in Brazil's maiden World Cup championship run.

Eight years earlier, seeing his footballer father cry when Brazil lost the 1950 World Cup final at home to Uruguay, Pele had promised to bring the trophy home one day.

"In 1958, in Sweden, I was walking through the streets thinking about fulfilling the promise I made to my father," Pele wrote.

"I know that many of the national team made similar promises and are also looking for their first World Cup. I want to inspire you, my friends... We are on this journey together. Good luck to our Brazil!"

Pele -- whose real name is Edson Arantes do Nascimento -- has been in fragile health in recent years.

Diagnosed with a colon tumor in September 2021, he underwent surgery to remove it the same month. He has been receiving chemotherapy ever since, but doctors said he now needed a "reevaluation" of his treatments.

His medical team says he also has a respiratory infection, which they are treating with antibiotics.

Pele's daughter Kely Arantes Nascimento said Sunday the new illness was the result of a Covid-19 infection Pele, who is fully vaccinated, contracted three weeks ago. 

She and her sister Flavia told Brazilian TV network Globo that Pele's family and doctors are confident his health is not at grave risk.

"He is sick, he is elderly, but at this point he is hospitalized for a lung infection," said Nascimento.

"When he gets better, he'll come home."

Flood of tributes

Worried fans have been keeping vigil outside the Albert Einstein Israelite Hospital in Sao Paulo, praying for Pele's recovery.

Tributes have also poured in from around the world, including in Qatar, where World Cup organizers lit up buildings with the message "Get well soon" and deployed dozens of drones to draw a Brazil jersey in the night sky over Doha with Pele's iconic number 10 on it.

Brazil coach Tite said Thursday the football world was rooting for Pele, "our greatest representative, the extraterrestrial who is terrestrial."

Current stars such as France striker Kylian Mbappe and England captain Harry Kane have also sent messages of support.

"Pray for the King," Mbappe wrote on Twitter.