The set stayed on serve until Del Potro secured the first break point for a 4-3 lead.
5-7 win over Frenchman Gilles Simon after fading light interrupted their last-16 clash the previous evening with the fifth seed up two sets to one.
Serbia's Novak Djokovic celebrates winning his quarter final match against Japan's Kei Nishikori. He said the only time he has played on Centre Court was during the London Olympics, and admitted: "I have no clue what that court looks like". "I've tried to build the momentum and I've been very pleased with the way I've been playing in the grass court season". In a four-set match that went on for two hours and 35 minutes, the 12-time Grand Slam title victor, and three-time Wimbledon champion, was in control despite dropping the second set.
When he lost in the French Open quarter-finals to world number 72 Marco Cecchinato last month, he even suggested he was ready to skip Wimbledon this year as his ranking slipped to 22, his lowest since August 2006.
Nadal soon returned the favour with a break of his own, before another hold left Del Potro rattled.
Nadal and Djokovic have faced each other 51 times in total with the Serbian shading it with 26 wins but the Spaniard has won their last two meetings. He is one of the more complex players that I have ever seen in our sport, it is always a big test.
"He deserved to win today". Del Potro made him pay as he pounced on his first chance to raise the prospect of another upset on day nine.
ACLU: Trump administration should pay counseling for separated families
The agency didn't respond to Business Insider's request for comment on why six of the intended 63 children weren't reunited. A court-imposed deadline to reunite immigrant children under five with their parents by July 10th will likely not be met.
"For the rest of the things, great news, semi-finals of Wimbledon again".
Isner, who leads Anderson 8-3 in past meetings, is making his debut in the final four of a Grand Slam tournament in his 41st appearance at one.
THEY say there's no such thing as a free lunch but if you share a name with one of two famous tennis players you could be enjoying just that this week. We have always played on important stages, important places. You know that you can not win against Novak if you don't play well.
And the people back home who saw Isner grow up or just follow his pro tennis career have been watching this magical fortnight at Wimbledon.
It is the first time since he reached the Australian Open and French Open quarterfinals in 2012 that del Potro has qualified for the last eight at consecutive Grand Slams.
While both of those Nadal victories came on clay, they may set the tone for how this match begins. "Physically I've felt awesome".
"I'm not thinking about being an underdog or a favourite", Djokovic said after his quarter-final.