Del Potro has looked one of the biggest threats to Nadal's domination this year, with his pulverising forehand dismantling everyone in his path on the Parisian clay.
After dropping the opening set of his first round match he won the next 12. Cilic, who like Del Potro stands 1.98m tall, owns a U.S. Open title, has a beast of a serve and always looked like being his first serious test. And so it proved.
After returning to a sunny Court Suzanne Lenglen locked at 5-5 in the first set tiebreak after battle was halted because of rain on Wednesday, Del Potro flirted with danger before racking up an eighth win in succession against Cilic.
He appeared almost overcome with emotion after reaching his first French Open semi-final since 2009, when he was beaten by eventual champion Roger Federer.
"Well, it's tough to speak," the 29-year-old, who has risen back to sixth in the rankings after battling back from three left wrist surgeries, said on court as fans sang "Delpo, Delpo".
Asked about facing Nadal, who he has beaten five out of 14 times but never on clay, he was drowned out by his fans who clearly believe in their man's chances.
'BIG LOVE'
"It's a challenge that every player wants to have," he said. "I don't know if I will win, but I will take big love from you and that's most important for me."
The first set always looked key and Del Potro clinched the opener as Cilic blinked first.
Del Potro said resuming a match at 5-5 in a tiebreak with his serve to come had been a strange situation but his aim was true and he moved 6-5 ahead before his cagey backhand slice induced a poor forehand error by Cilic.
"It was very important to win the first one. It wasn't a good night because I was thinking too much, where could I serve, "T" or wide? (Smiling). I made too many questions to myself.
"But then I got lucky to win the first set, playing two good points. It was like a new match after the first set."
The second set, like the first, was dominated by serve until Cilic fired himself up to break at 4-4 -- a furious Del Potro throwing his racket at the changeover.
Croatian Cilic played an awful game when serving for the set, making four unforced errors, but he was gifted another chance to serve it out after breaking Del Potro again and levelled the match at the second time of asking.
Del Potro, who had words with a fan who had shouted out during a serve, looked rattled and he was a point away from going a double break behind in the third set.
"I'm still trying to find the right person," he joked.
The burly Argentine recovered his usual unflustered demeanour, hitting back from 0-2 to take the third set.
Former Roland Garros junior champion Cilic, bidding to reach the semi-finals for the first time after falling in the quarter-finals 12 months ago, kept his nose in front in the fourth.
But Del Potro bided his time, applied some pressure at 5-5 and Australian Open runner-up Cilic cracked.
Serving for the match Del Potro was given an easy ride as Cilic blazed three backhands in succession long.
(Reporting by Martyn Herman; Editing by Pritha Sarkar/David Goodman/Toby Davis)
Share
