In one epic 14-point game early in the deciding set, such was the desperation of both combatants that del Potro twice left the ground trying to retrieve balls at the net before Nadal went hurtling over a barrier, into the stands and onto jaw-dropping spectators' laps.
Djokovic and Nishikori will play the first match on Centre Court, followed by arguably the pick of the quarter-finals between Nadal and Juan Martin del Potro, meaning Federer must make a rare visit to Court One. I tried to resist, maintaining focus.
The 32-year-old's prize is a clash on Friday with first-time grand slam semi-finalist John Isner, who ousted 2016 runner-up Milos Raonic 6-7 (5-7) 7-6 (9-7) 6-4 6-3 in a serving shootout featuring 56 aces in four sets.
Nadal is chasing an 18th Grand Slam title which would put him just two behind Roger Federer who was sensationally knocked out in the quarter-finals by Kevin Anderson.
They have met on 51 previous occasions, but not at this stage of a Slam since the 2014 French Open semi-finals.
However, the pair's last encounter was more than three years ago - at the Indian Wells Masters - and Anderson has made significant strides since then.
Cotorro said: 'What you note the most the following day is the muscle fatigue, because these courts are very exigent, you play in unusual areas.
"Emotional match for both of us", said Nadal, who is ranked No. 1 and seeded No. 2 and won two of his 17 major championships at Wimbledon.
A set littered with one lengthy rally after another, eventually went to Nadal on serve, finally giving him the match. Isner is 8-3 against Anderson, and this will be his first career semifinal at a major.
"For the rest of the things, great news, semi-finals of Wimbledon again".
"I said at the beginning of the tournament, getting through to the quarters was a big goal of mine", he said.
He lost to Nadal in last year's US Open.
"But also putting myself in these positions where hopefully I'm able to get another step forward and be playing on Sunday". "I really do. I think with the performances I've had, I deserve to be in the semifinals", he continued.
"With how I'm feeling physically and mentally, I'm in a very good spot".