Del Potro suffered more heartbreak after losing to Nadal in the semifinals at Roland Garros last month, his 52 unforced errors proving to be costly as the Spaniard claimed the only break in a pulsating final set.
"Of course I'm sorry for Juan Martin".
World number one Nadal saw off Del Potro 7-5, 6-7 (7/9), 4-6, 6-4, 6-4 after four hours and 48 minutes on Centre Court to reach his sixth Wimbledon semi-final and 28th at the majors.
After so much speculation about a possible Wimbledon final between Roger Federer and Rafael Nadal, 10 years after their last, the tennis world instead will get a semifinal featuring another outstanding rivalry: Nadal vs. Novak Djokovic. "I'm a different person, different player today", Djokovic said. "He's playing well. Only way to try to win it is (to) play very well".
All four semi-finalists are aged 30 or over - the first time in the Open era that the men's singles semis at a Grand Slam have been contested exclusively by players over 30.
In the biggest upset of this year's Wimbledon Championship, Anderson beat world number one Federer in a sprawling five-set epic lasting four hours and 14 minutes. It was an honour to share the court with you.
It was not as if Nadal was playing badly as he had lost only nine points on serve before heading into the ninth game of the second set.But just before that game started, Federer's shock demise was flashed up on the giant on-court scoreboard and it was as if that threw the Spaniard off his stride and he fluffed his lines to drop his serve.
After seven weeks out with a serious knee injury, many doubted if Nadal would regain his crown as the "King of Clay".
Rafael Nadal described long-time rival Novak Djokovic as "one of the more complex" players he's ever met as they prepare to clash for the 52nd time on Friday with a Wimbledon final spot at stake. However many times he's lost to Djokovic in the past-and that includes the 2011 Wimbledon final-he's now No. 1 and coming off a major title in Paris, while Djokovic is still climbing his way back up the charts.
"Of course I was anxious when I lost the second set", Nadal said.
"Anything could happen, so this is a big achievement for me to get to the semi-finals at Wimbledon".
Isner - a college jock type never spotted without a backwards baseball cap - enjoyed his breakthrough moment earlier this year in Miami when he won his first Masters title. I went to the net. In some ways he deserves to win as well.