Paris (AFP) - World number one Andy Murray set up a French Open blockbuster against Juan Martin del Potro on Thursday, the latest chapter in what has developed into an epic rivalry.
Murray, the 2016 runner-up, reached the third round with a bruising 6-7 (3/7), 6-2, 6-2, 7-6 (7/3) win over Martin Klizan of Slovakia.
Del Potro, playing in Paris for the first time in five years, went through after Nicolas Almagro retired in tears with a knee injury.
The giant Argentine was immediately hailed for his sportsmanship when he embraced and consoled the sobbing, stricken Spaniard courtside.
Out on Suzanne Lenglen court, world number 50 Klizan smashed 57 winners but 67 unforced errors as his all-or-nothing game proved in vain against top seed Murray.
"I expected a tough match. Martin goes for his shots, he can hit winners with that forehand from anywhere on the court," said Murray.
The Scot beat Del Potro in a marathon Olympic final in 2016 before the Argentine, now 30 in the world, gained his revenge with a come-from-behind win in five sets in the Davis Cup semi-final.
"It will be very tough. Juan Martin is playing a lot better than his ranking," said Murray as he looked ahead to Saturday's clash.
Del Potro, no stranger to injury after a career-long battle with wrist problems, made the third round after Almagro quit in tears during the third set with a left knee injury.
In a moving conclusion on Court Two, Del Potro sat next to a sobbing Almagro, offering him water while trying to to console the heartbroken 31-year-old.
Del Potro had also gone to the Spaniard's aid when he had collapsed at the back of the court, weeping, just moments earlier.
- 'Heart first' -
"I tried to find good words for him at that moment. I say to him, try to be calm. Try to think about his family, his baby," said Del Potro.
"Sometimes the heart is first more than the tennis match."
Del Potro, 28, had taken the first set 6-3 before Almagro claimed the next by the same score.
They were locked at 1-1 in the third when Almagro quit.
Del Potro also suffered an injury scare himself when he pulled up, holding his left groin in the second set.
Third seed Stan Wawrinka, the 2015 champion, reached the last 32 for the 10th time with a 6-4, 7-6 (7/5), 7-5 win over Alexandr Dolgopolov of Ukraine.
Wawrinka will face Italy's Fabio Fognini for a place in the fourth round.
Japanese eighth seed Kei Nishikori routed France's Jeremy Chardy 6-3, 6-0, 7-6 (7/5) and set up a rare all-Asian clash with South Korean Hyeon Chung.
Chung, the 21-year-old world number 67, followed up his first round win over US 27th seed Sam Querrey with a 6-1, 7-5, 6-1 victory against Denis Istomin of Uzbekistan.
Nick Kyrgios's Australian Open ended in a 5-7, 6-4, 6-1, 6-2 loss to big-serving Kevin Anderson of South Africa.
Anderson, ranked at 56 in the world, made the most of the 18th-seeded Australian's 42 unforced errors to progress.
Unseeded 21-year-old Karen Khachanov of Russia continued his impressive debut, beating Czech 13th seed Tomas Berdych, a semi-finalist seven years ago, 7-5, 6-4, 6-4.
In the women's event, Czech second seed Karolina Pliskova and third-seeded Simona Halep of Romania, both firm women's title favourites after the first round exit of world number one Angelique Kerber, went through.
Pliskova, 25, reached the third round for the first time at the seventh attempt but had to fight to see off Russian world 86 Ekaterina Alexandrova, 6-2, 4-6, 6-3.
Halep, the 2014 runner-up, cruised to a 6-4, 6-3 win over Germany's Tatjana Maria.
However, crowd favourite Eugenie Bouchard's struggles continued with a 6-3, 6-0 loss to Latvian 17th seed Anastasija Sevastova.
Fifth seed Elina Svitolina, a quarter-finalist in 2015 and recent Rome champion, fought back to beat Bulgaria's Tsvetana Pironkova, a quarter-finalist last year, 3-6, 6-3, 6-2.
Poland's Agnieszka Radwanska, seeded nine, saw off Belgian qualifier Alison Van Uytvanck 6-7 (3/7), 6-2, 6-3.