Roger Federer, Rafael Nadal, Carlos Alcaraz and Gael Monfils appeared in a video tribute to the Argentinian.
Del Potro defeated five-time defending champion Federer to win the US Open in 2009.
He reached the final in New York again in 2018 but lost to Djokovic.
A popular player with a big forehand, Del Potro won two Olympic medals – bronze in 2012 and silver four years later.
He claimed 22 ATP singles titles in his career and was ranked third in the world.
However, a wrist injury derailed his career after his US Open win before he seriously injured his knee at Queen’s in 2019.
Del Potro released a video on Instagram last week, outside discussing the long-term impact of the injury on his body.
“My daily life is not the way I want it to be. It’s very difficult. There are times when I don’t have the strength anymore,” he said.
“I’m not indestructible. I have good things and bad things, but often I have to pretend and put on a good face, but most of the time I feel bad.
“Since then (after surgery in 2019), I have never been able to climb stairs without pain.
“I get sick when I drive, often hurt when I go to sleep. It’s a never-ending nightmare.”
