The 11th-seeded Schwartzman appeared to have done his homework well as he dominated the early exchanges to bag the opening set - an achievement in itself as it was the first one Nadal had lost at Roland Garros since 2015.
The unheralded Cecchinato simply being here is freakish for a number of reasons, not least his 10-8 final set success over Marius Copil in the first round, a match which lasted nearly four hours.
Sharapova didn't need to play a point in the fourth round, because Serena Williams pulled out of their much-anticipated match with an injured chest muscle. Nadal hopes to make his 11th French Open final appearance. The 32-year-old Spaniard is 84-2 for his career at the French Open, winning four consecutive titles from 2005-08, another five consecutive from 2010-14, and No. 10 a year ago.
Nadal giving up a 6.5 game head start is [1.74] on the Exchange, and I'd expect this to rise by several ticks as the market forms in the run-up to the match, and I'm quite happy to look at this as a more viable proposition.
Muguruza has not dropped a set so far in this year's tournament as she seeks a second championship in Paris and third major trophy overall.
But he returned 30-15 up and serving to level the match after fighting back from a break down in the second set between rain delays the previous evening. "I've still got a long time left, I can keep playing until I'm 41".
In brighter and quicker conditions than those of Wednesday, Nadal's experience told as he came out more aggressively and swept away his 5' 7' opponent, who had made such a gallant run to the last eight.
When Cilic's final forehand flew wide, del Potro stood legs wide apart, arms aloft, soaking in the crowd that appreciated the effort not just of the match, but of the resolve.
Back in 2009, it was Federer who stopped del Potro in Paris.
"I don't know if I will win, but I will take a big love from you", Del Potro told the crowd. This really changed totally how I was looking at the match and how my opponent was looking at the match. He went on to win the U.S. Open the same year by defeating Federer in the final. "It has been a long time without good feelings".
Afterwards a tearful Del Potro said on courtside: "It's tough to speak now".
Sloane Stephens' clash with Madison Keys represented a rematch of the 2017 US Open final, which Stephens won.
Two women who have won the title at Roland Garros, Maria Sharapova and Garbine Muguruza, play each other in the quarterfinals.
"I thought that after nine years I will play a different one, not Rafa or Roger", he added.