The fifth-seeded del Potro failed to convert four match points when serving at 5-4 in the fourth set, but maintained his composure to close out the contest with his first opportunity in the tiebreaker that followed.
Only in this last 18 months has he been able to restore his glory, with successive French Open titles, and a US Open victory. He picked himself up and dusted himself down to play on for another eight games, but it was a different story an hour later when there was nothing left to fight for. "He deserves to win today and keep winning", said the 29-year-old Argentine. After nearly five hours, I fell down. "It's a great spotlight on college tennis that one of us is going to be in the Wimbledon final".
A set apiece, both won 6-4, ensured the match went to a decider, but Nadal held his nerve in a marathon final set.
The world number one then wasted four set points in the second. That double fault was a big mistake. Del Potro made him pay as he pounced on his first chance to raise the prospect of another upset on day nine.
"I have done a lot of things well since I came back from injury".
Not only has he cracked 161 aces, more than anyone else and 48 ahead of Anderson, who is no slouch with ball in hand, but he has topped the tournament table for accuracy, landing 405 of 535 first serves in the box, conceded only seven break points and saved them all, way above the average of 64%, and has won all his 95 service games.
A tired Del Potro, a semi-finalist in 2013, finished with 33 aces and 77 winners but even those impressive statistics were not enough. He played for a lot of time in tense situations, which helps.' About Djokovic, Roig finally said: 'He is getting to his level.
The semi-final clash between Rafael Nadal and Novak Djokovic will be their 52nd career meeting.
President Cyril Ramaphosa on Thursday led South Africa in congratulating Kevin Anderson after he sensationally knocked Roger Federer out of Wimbledon to become the first South African to reach the semi-finals in 35 years.
"Sorry to Juan Martin, he´s an fantastic opponent and player". I know in the semi-finals of Wimbledon you will not have an easy opponent.
"The last set had a little bit of everything, great points, great rallies, he was hitting insane with his forehands".
'Obviously at the end of this day, analyse things that I've done right, that maybe need some improvement, focus on the next day's practice session, recovery.
"This is going to be an emotional match for both of us", said Nadal. "I've put myself in with hopefully a shot to be playing again on Sunday".