He will play the 10 time champion Rafael Nadal who progressed to a record 11th French Open semi-final with a four set victory over the 11th seed Diego Schwartzman.
"I've been a long time without feeling good with my body,” said Del Potro. “I had surgery three times on my wrist and I was close to quitting this sport. I don't have words to explain what this means to me and my team."
The fifth seed registered his eighth consecutive victory over Cilic. On Friday he will face arguably the toughest test in clay court tennis when he takes on the 10-time champion Nadal for a place in Sunday's final.
Nine years ago in the semi-final, Del Potro lost to Roger Federer who went on to win the title against Robin Soderling.
Del Potro, who beat Federer to win the 2009 Us Open, said he was impressed with the longevity of the so called Big Four of Federer, Nadal, Novak Djokovic and Andy Murray. "Well, I thought that after nine years I would play a different person, not Rafa or Roger. But all my semi-finals in Grand Slam were against them.
“The last one at the US Open I lost against Rafa. In Wimbledon I lost against Djokovic. Here in Paris against Federer.
"It's a big challenge to play them in Grand Slams. But I think they show how good they are at playing Grand Slam because, after 10 years, they are fighting to win these kind of tournaments. It's amazing for the tennis world."