PARIS (AP) -- That Rafael Nadal would reach a record 11th French Open semifinal, closing in on his 11th championship at Roland Garros, was hardly surprising.
That he trailed by a set and a break before rain delays allowed him to change tactics and recover to get there? Now that, certainly, was unusual.
His opponent Friday will be Juan Martin del Potro, who got choked up after waiting nearly a decade to return to the final four in Paris -- and dealing with three wrist operations in the interim.
Both men advanced by winning quarterfinals suspended the night before because of rain. The No. 1-ranked Nadal quickly announced Thursday that he was not going to be as passive as he was in the early going against 11th-seeded Diego Schwartzman, seizing 12 of the initial 13 points after they stepped out under a blue sky and pulling away for a 4-6, 6-3, 6-2, 6-2 victory at Court Philippe Chatrier.
"Totally different guy yesterday," Schwartzman said. "Maybe the day when you can beat Rafa was yesterday."
Across the way at Court Suzanne Lenglen, No. 5 del Potro got distracted by a spectator right before a key double-fault, then marched over toward the stands to try to figure out who it was.
Otherwise, he stayed steady in a 7-6 (5), 5-7, 6-3, 7-5 win over No. 3 Marin Cilic in a matchup between two past U.S. Open champions.
The other men's semifinal is No. 7 Dominic Thiem of Austria against 72nd-ranked Marco Cecchinato of Italy, who never won a Grand Slam match until last week and was cleared of a match-fixing charge on a technicality in 2016.
After del Potro served out his victory at love to get to his first semifinal at the clay-court Grand Slam tournament since 2009, he sat in his changeover seat, chest heaving.
The 6-foot-6 (1.98-meter) Argentine wiped away tears during his on-court interview, telling fans who chanted his nickname, "delPo": "It has been a long time without good feelings on my body. ... I was close to quit this sport. And now I don't have any words to describe this moment. It's so good for me, for my team, for my family."
Now comes what del Potro called "the challenge that every player wants to have" -- taking on Nadal at Roland Garros. 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.
Broaden the scope to all best-of-five-set matches on red clay, and his record is 109-2.
And yet, insists Nadal: "I just go on court knowing that every match is difficult, and I can lose and I can win."
There was a stretch Wednesday when it did seem as if Schwartzman might have a chance to become only the third man to beat Nadal at the French Open, joining Robin Soderling (fourth round, 2009) and Novak Djokovic (quarterfinals, 2015).
Nadal had not even dropped a set in the tournament since that match against Djokovic, a run of 37 in a row that ended in the opener against the 5-foot-7 (1.70-meter) Schwartzman, an Argentine eyeing his first appearance in a major semifinal.
Schwartzman compiled a 20-4 edge in winners in that first set, then broke Nadal for the fifth time in eight service games and was ahead 3-2 in the second when a rain delay of just under an hour arrived.
"I was a bit lucky," said Nadal, who is 10-0 in French Open semifinals and 10-0 in finals at the tournament. "Gave me time for reflection, to calm my nerves and to see how I needed to change things."
When they returned to the court, Nadal used a burst of three straight games -- and 13 of 15 points -- to close in on taking the second set. He was serving for it at 5-3, 30-15 when a new shower ended play for the day.
Nadal wrapped up that set by winning the first two points played Thursday and he was on his way, never relenting.
"He was playing great, and I was playing too defensive. I felt that I was playing a little bit under more stress than usual, and he was able to take control of the point too many times," Nadal said about the match's start.
And after the rain?
"I played more aggressive," Nadal said, adding: "In my opinion, the match changed, no?"