Paris - Juan Martin Del Potro said he felt deeply sorry for stricken opponent Nicolas Almagro after a knee injury forced the Spaniard to retire from their French Open clash on Thursday.
The towering Argentine advanced to a third-round showdown with Andy Murray after Almagro collapsed to the court in tears at 1-1 in the third set on Court Two.
Del Potro quickly hurdled the net to console a sobbing Almagro, who arrived in Paris having been forced to retire with a knee injury at the Rome Masters.
"Today I think I got lucky, because I don't feel good enough with my body, and then Nico felt something wrong in his knee and he decides to retire," said Del Potro, who had taken the first 6-3 before Almagro claimed the second by the same score.
"It's an unpleasant feeling. You have a player who is suffering quite a lot.
"He was in agony. It was tough. I told him that tennis is important, but health matters more than tennis in this case."
Former US Open champion Del Potro is no stranger to injury, with the 28-year-old appearing at Roland Garros for the first since 2012 after being pushed to the brink of retirement.
The Argentine has battled a series of wrist injuries throughout his career and was a doubt himself for the French Open with shoulder and back concerns.
"I know what injuries are all about. Something I don't wish on anyone. So it was sad. I was sad, as well," said Del Potro, seeded 29th in Paris.
"I wish a good recovery to Nico. Hopefully he can feel better very, very soon, because he's a great player and we love to have him on tour.
"And of course it's not easy for me when you have a friend in the other side of the court showing an injury or crying. It was really a bad moment for both, but I wish all the best to him."
Del Potro tweaked his groin in the opening set, impeding his movement, and took anti-inflammatory tablets but said he wasn't overly concerned.
"I will have two days in order to rest and recover. It's not new. Last year I had some problems with my groin. It's not a source of concern. This is something that I have experienced already," he said.
"Hopefully I can be in good shape, because I would like to play 100% in the third round, and I'm feeling good with my game at this moment, but I need to be in good shape, as well."
Del Potro and world number one Murray, who clawed past Slovakia's Martin Klizan in four sets, met in two epic encounters last year.
Murray beat the Argentine in a marathon Olympic final before Del Potro, now 30 in the world, gained his revenge with a come-from-behind win in five sets in the Davis Cup semi-final.
"Last year we waged fiercely contested battles. So the stakes are high," admitted Del Potro. "Andy is one of the favourites to win this tournament."
French Open results on Thursday, the fifth day of the 2017 tournament at Roland Garros (x denotes seeding):
Andy Murray (GBR x1) bt Martin Klizan (SVK) 6-7 (3/7), 6-2, 6-2, 7-6 (7/3)
Juan Martin Del Potro (ARG x29) bt Nicolas Almagro (ESP) 6-3, 3-6, 1-1 -- retired
John Isner (USA x21) bt Paolo Lorenzi (ITA) 6-3, 7-6 (7/3), 7-6 (7/2)
Karen Khachanov (RUS) bt Tomas Berdych (CZE x13) 7-5, 6-4, 6-4
Fernando Verdasco (ESP) bt Pierre-Hugues Herbert (FRA) 6-3, 3-6, 4-6, 6-3, 6-3
Pablo Cuevas (URU x22) bt Nicolas Kicker (ARG) 6-4, 6-4, 6-4
Hyeon Chung (KOR) bt Denis Istomin (UZB) 6-1, 7-5, 6-1
Kei Nishikori (JPN x8) bt Jerrmy Chardy (FRA) 6-3, 6-0, 7-6 (7/5)
Stan Wawrinka (SUI x3) bt Alexandr Dolgopolov (UKR) 6-4, 7-6 (7/5), 7-5
Fabio Fognini (ITA x28) bt Andreas Seppi (ITA) 6-4, 7-5, 6-3
Richard Gasquet (FRA x24) bt Victor Estrella Burgos (DOM) 6-1, 6-0, 6-4
Gael Monfils (FRA x15) bt Thiago Monteiro (BRA) 6-1, 6-4, 6-1
Kyle Edmund (GBR) bt Renzo Olivo (ARG) 7-5, 6-3, 6-1
Kevin Anderson (RSA) bt Nick Kyrgios (AUS x18) 5-7, 6-4, 6-1, 6-2
Feliciano Lopez (ESP) bt David Ferrer (ESP x30) 7-5, 3-6, 7-5, 4-6, 6-4
Marin Cilic (CRO x7) bt Konstantin Kravchuk (RUS) 6-3, 6-2, 6-2
Elina Svitolina (UKR x5) bt Tsvetana Pironkova (BUL) 3-6, 6-3, 6-2
Magda Linette (POL) bt Ana Konjuh (CRO x29) 6-0, 7-5
Anastasija Sevastova (LAT x17) bt Eugenie Bouchard (CAN) 6-3, 6-0
Petra Martic (CRO) bt Madison Keys (USA x12) 3-6, 6-3, 6-1
Elena Vesnina (RUS x14) bt Varvara Lepchenko (USA) 4-6, 6-3, 6-0
Carla Suarez Navarro (ESP x21) bt Sorana Cirstea (ROM) 7-5, 6-4
Daria Kasatkina (RUS x26) bt Marketa Vondrousova (CZE) 7-6 (7/1), 6-4
Simona Halep (ROM x3) bt Tatjana Maria (GER) 6-4, 6-3
Hsieh Su-Wei (TPE) bt Taylor Townsend (USA) 6-0, 2-6, 6-3
Caroline Garcia (FRA x28) bt Chloe Paquet (FRA) 7-5, 6-4
Alize Cornet (FRA) bt Barbora Strycova (CZE x20) 6-4, 6-1
Agnieszka Radwanska (POL x9) bt Alison Van Uytvanck (BEL) 6-7 (3/7), 6-2, 6-3
Veronica Cepede (PAR) bt Anastasia Pavlyuchenkova (RUS x16) 7-6 (7/4), 2-6, 6-4
Mariana Duque (COL) bt Magdalena Rybarikova (SVK) 1-6, 6-3, 8-6
Carina Witthoeft (GER) bt Pauline Parmentier (FRA) 6-4, 7-6 (7/5)
Karolina Pliskova (CZE x2) bt Ekaterina Alexandrova (RUS) 6-2, 4-6, 6-3