Paris - Rafael Nadal insisted he still "feels pressure" and is "only human", after battling back from a set down to beat Diego Schwartzman on Thursday and set up a French Open semi-final clash with Juan Martin del Potro.
The 10-time champion was much-improved under the sunshine on Court Philippe Chatrier after finding life difficult the night before, clinching a 4-6, 6-3, 6-2, 6-2 victory over dogged Argentinian Schwartzman on his fourth match point.
It is the 11th time the 32-year-old Spaniard has reached the French Open last four, becoming only the third man in history to achieve the feat at a Grand Slam tournament, after Jimmy Connors at the US Open and Roger Federer at Wimbledon and the Australian Open.
"I don't have any obligation to win, first thing. Second thing, if you don't feel the pressure, it's because you don't love the sport," said Nadal, who has never failed to win the title in Paris after reaching the semi-finals.
"Pressure is good. You are able to control that. That pressure, that adrenaline, can be in a positive way."
The 16-time Grand Slam champion was pushed for three hours and 42 minutes by 11th seed Schwartzman, but will face Del Potro for a place in the final after the fifth seed downed Marin Cilic 7-6 (7/5), 5-7, 6-3, 7-5.
When asked why he still felt stress before resuming on Thursday despite all of his past achievements, Nadal said: "(Because) I am a human person.
"Sometimes you play better, sometimes you are more nervous."
In dropping the opener on Wednesday, Nadal had lost a set at Roland Garros for the first time since a 2015 quarter-final defeat by Novak Djokovic.
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.
It took Nadal just two quickfire points to wrap up the set and leave the two players with effectively a best-of-three set match to play on Thursday.
The top seed would have been delighted to return in his favoured hot conditions after the gloom of the night before, and a hasty end looked in sight when Nadal opened up a 4-1 third-set lead with a double break courtesy of a booming forehand followed by the cutest of drop shots.
Schwartzman, who came back from two sets down to beat Kevin Anderson in the last 16, rediscovered his form, but it came too late to save the set as Nadal served it out in a marathon eighth game on his second set point after saving four break points.
And despite a late stutter as Schwartzman saved three match points, Nadal wrapped up victory to keep alive his hopes of equalling Margaret Court's record of winning a single Grand Slam singles title 11 times.
The injury-plagued former US Open champion Del Potro wept courtside after beating third seed Cilic to reach the last four for the second time, but first in nine years.
"It's tough to speak now," said an emotional Del Potro.
"I've been a long time without feeling good with my body. 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 has now beaten Cilic, who made 74 unforced errors, eight times in a row, but on Friday he will face arguably the toughest test in tennis against Nadal on Court Philippe Chatrier.
Del Potro, the US Open winner in 2009, is playing the tournament for only the second time since 2012 after a spate of injuries.
The 29-year-old missed the event for four straight years before a third-round loss in 2017, but has regained fitness in recent months and reached the semi-finals at the US Open last year, where he lost to Nadal.