After reaching the French Open semifinals last month, Del Potro - who has missed long periods with a career-threatening left wrist injury - returned to his career-high ranking of No. 4 for the first time since February 2014, which he acknowledges is a "good signal".
Nadal described Wednesday's showdown as a combination of "suffering" and "enjoyment" but he was mightily relieved he came back from two-sets-to-one down to reach the semi-finals for the first time since 2011.
Del Potro kept Nadal on the baseline with a powerful return.
"If I want to beat him, I have to come to the net very often and play hard with my forehands, with my backhands, and try to take all the chances".
The incident was just a small part of a truly monumental encounter as the Centre Court of SW19 was scene to what is likely to be one of the greatest tennis matches of the year. "If Del Potro is physically there - I saw some of his match against Gilles Simon on Monday and he seemed to have some issues - that's not an easy match". "I think Rafa, in the end deserves to win once again".
Del Potro was straining to stay in touch in almost every point, and his gambling instincts drove him to explore the white lines. He must get past three-time champion Novak Djokovic in the semi-finals on Friday for another shot at the title.
The Serbian, a three-time victor, beat Japanese Kei Nishikori in a four-set match earlier on Wednesday at Centre Court.
The more gusty conditions on No. 1 Court could make Federer's challenge against eighth-seeded Kevin Anderson more complicated.
The 32-year-old looks refreshed following his decision to pull out of Queen's and now, unlike Del Potro, has had the benefit of a day off.
Djokovic had been yearning for a Centre Court date, after playing as many games on Court Two as the main show court beforehand in this tournament.
"It will be a different match that we played in Paris few weeks ago", he said. He played well. I believe I increased little bit the level in the fourth and the fifth. I was close to beating him and I couldn't.
"I´m glad to play in this level against the No. 1 in the world". El Espanol revealed it. 'I am coming from being in the cold water and now I have to rest', Nadal said in his post-match press conference at around 10:00 PM. Wednesday proved to be a special day at the Wimbledon 2018 with two spectacular matches in the Men's singles.