Novak Djokovic survived a quarter-final scare from Karen Khachanov to keep his bid for a record 23rd men's Grand Slam singles title alive at the French Open.
Djokovic was in danger of falling two sets behind against the Russian but prevailed 4-6 7-6 (7-0) 6-2 6-4.
He could become the first man to win all four majors at least three times.
Djokovic's win sets up a potential semi-final with world number one Carlos Alcaraz, who faces Stefanos Tsitsipas in Tuesday's night session (19:15 BST).
The Serb had not dropped a set all tournament on the Paris clay but Khachanov provided the test he arguably needed to prepare him for either Alcaraz or Tsitsipas in the last four.
Having faced seven break points - saving six of them - in losing the opening set, Djokovic tightened up his service game for the majority of the match thereon.
And while the 36-year-old was kept on court for three hours and 43 minutes, the outcome never really looked in doubt once he comprehensively won the second-set tie-break.
"I played the perfect tie-break and from that moment onwards I played a couple of levels higher than I did at the beginning," Djokovic said in his on-court interview.
"It was a big fight, it's what you expect in the quarter-finals of a Grand Slam. You are not going to have your victories handed to you and I'm glad to have overcome it today."
Unrelenting Djokovic outlasts valiant Khachanov
Djokovic came into the match having won 29 successive sets in Grand Slams but Khachanov ended that streak in just under an hour on Court Philippe Chatrier.
The world number 11 matched Djokovic in the returning stakes - not usually a Khachanov strength - early on and finally broke serve in a marathon fifth game after seeing four previous break points saved.
He served out the set, despite a typically-dogged Djokovic saving three set points, two on his own serve and one on Khachanov's.
Neither player earned a single break point in a serve-dominated second set, which Djokovic claimed in clinical fashion without dropping a point in a one-sided tie-break.
A fortunate net-cord handed Djokovic a break of serve in a lengthy opening game of the third set and he rarely looked back from there as Khachanov's challenge discernibly faltered.
The Russian had never beaten a top-five player in a Grand Slam or on clay, holding 0-8 records in both categories, and the belief he showed in the opening two sets began to desert him.
Khachanov still showed quality to test Djokovic in patches, particularly late in the fourth set where he threatened a revival by breaking back from 3-1 down, but Djokovic won eight successive points from 4-4 to wrap up victory in style with an ace.
A ninth victory in 10 meetings with Khachanov sealed a 45th Slam semi-final appearance for Djokovic - one shy of the record held by Roger Federer - but it is the 'big one', the record 23rd men's title, that surely motivates him.
And with the injured Nadal absent - not just in Paris but probably for the rest of the year - the Spaniard will likely be looking to his compatriot Alcaraz to help him preserve his share of the Grand Slam title record.