Argentine soccer great Diego Maradona is in recovery after successful surgery to treat a subdural hematoma, a blood clot on the brain, the former World Cup winner's doctor announced.

The operation, after Maradona, 60, was admitted to hospital a day earlier, was to address the clot, often caused by a head injury, and which can put pressure on the brain.

"I was able to evacuate the hematoma successfully and Diego tolerated the surgery very well," Leopoldo Luque, Maradona's neurosurgeon and personal physician, told reporters outside the clinic where dozens of fans were gathered.

"The steps now are observation, but it is controlled. It will depend on how he does. It is not highly complex, but it is still brain surgery," Luque added, saying the procedure had taken around 80 minutes.

The intervention was potentially risky due to the ex-footballer's delicate general health, though Luque earlier said the procedure was "routine surgery" and that Maradona had been "lucid" and understood and agreed with the procedure.

Maradona was admitted to the Ipensa clinic in La Plata, Argentina, on Monday for anemia and dehydration, before being transferred to Olivos Clinic in Buenos Aires province.

Around 50 fans gathered in front of the Olivos Clinic, in the suburbs of Buenos Aires, celebrated when reports of the successful outcome started to emerge, chanting: "Diego, Diego!"

Maradona, who won the World Cup with Argentina in 1986 and is widely considered to be one of the greatest players of all time, coaches local club Gimnasia y Esgrima.

He last appeared in public on his 60th birthday last Friday before his side's league match against Patronato.

Maradona, who played for the likes of Napoli, Barcelona and Boca Juniors before hanging up his boots in 1997, is set to remain in a clinic in La Plata, south of Buenos Aires, for at least 48 hours as he recovers.

Argentina's all-time leading scorer Lionel Messi took to Instagram on Wednesday to wish his compatriot well.

Alongside a picture of the pair together, the Barcelona forward wrote in Spanish: "Diego, all the strength in the world. My family and I want to see you well as soon as possible. A hug from the heart!"

Dozens of fans of Gimnasia y Esgrima have converged on the hospital since Monday evening, waving flags and holding posters with messages of support as they waited for news.

"What we want the most is for Diego to get out of all this. He can be, he is the greatest, the greatest in the world," said Diego Bermudez, 41, a Maradona fan waiting outside the hospital.

Another fan, Oscar Medina, said: "Diego is fighting inside with medics. Hopefully God blesses the medics, to move on from this. His people are out here on the street, hearts beating."