So when opponent Nicolas Almagro -- a former French Open quarterfinalist -- had to retire from their second-round match at Roland Garros with a knee injury, del Potro went above and beyond the norm trying to console his dispirited friend.
Almagro -- who retired against Rafael Nadal in Rome last month with the same issue -- bent over, then fell backwards onto the court at 1-1 in the third set after the players split the first two sets.
Del Potro walked with a weeping Almagro towards the umpire's chair and after the Spaniard officially retired, the two shared a hug.
But that wasn't it. After slamming his water bottle to the clay in frustration, Almagro returned to his chair -- and was joined by del Potro, who hung around and offered words of encouragement to the new dad, whose son was born earlier this year.
"I'm very familiar with injuries," del Potro told reporters. "I know what injuries are all about. Something I don't wish on anyone. So it was sad. I was sad, as well.
"I tried to, I don't know, tried to find good words for that moment. I said to him, 'Try to be calm.' Try to think about his family, his baby.
"And sometimes the heart is first, (before) the tennis match or the tennis life."
Del Potro had his own physical issues in the encounter, and the wrists had nothing to do with it.
Having entered the French Open with shoulder and back complaints, he tweaked his groin versus Almagro and needed to take anti-inflammatory medication.
He was however hopeful of being fit for his much anticipated third-round duel with world No. 1 Andy Murray.
Murray tested again
Murray toiled against the talented, inconsistent Martin Klizan, prevailing 6-7 (3-7) 6-2 6-2 7-6 (7-3) -- rallying from a 5-2 deficit in the fourth set. This after Murray dropped a set in the first round against Andrey Kuznetsov.
Still it was an improvement from 12 months ago when Murray was stretched to five sets in the first two rounds, which likely took a toll in the final he lost to Novak Djokovic.
Murray and del Potro played each other twice last year and both were epics.
Murray won the Olympic final in Rio in four hours to successfully defend his London 2012 crown before del Potro defeated the Scot in five hours in Glasgow in the Davis Cup semifinals.
"We played great battles last year," del Potro said. "(Saturday) could be another great battle if I feel good.
"Andy is one of the favorites to win this tournament. And now I know his game a lot, but I need to be in good shape and physically be stronger to hold a long match if we play a long match, long rallies.
"I'm happy with my level at this moment, so my forehands and serves are working good. But anyways, I need all my body in good shape."
If del Potro's body might not be quite willing, his character certainly is.
Elsewhere on day five in Paris, Nick Kyrgios lost his cool -- and the match -- against South Africa's Kevin Anderson.
The 18th-seeded Aussie led by a set and 4-2 but failed to protect his advantage, falling 5-7 6-4 6-1 6-2. He was hit with a point penalty to begin the third set after destroying his racket.
"My preparation for the clay court season hasn't been great," said Kyrgios, who missed the Rome Masters with a hip injury and skipped Estoril after his grandfather died. "I feel like I've way underdone coming into the French."
With women's No. 1 seed Angelique Kerber eliminated in the first round, Karolina Pliskova and Simona Halep -- perhaps the tournament favorite -- are the two highest seeds remaining.
The duo progressed to move closer to a semifinal showdown.
Pliskova would do well to get there since clay isn't her preferred surface. The Czech -- a finalist at the hardcourt US Open in September -- dropped a set to 86th-ranked Russian Ekaterina Alexandrova on Thursday and went 4-4 on the clay leading into the French Open.