"It's a great feeling to be back".
"No, probably will be better to come back in the best of three sets, not best of five sets", Nadal was quoted as saying by the Express.
Holders France took a 2-1 lead in their tie with Italy as Pierre-Hugues Herbert Nicolas Mahut comfortably beat Simone Bolelli and Fabio Fognini 6-4 6-3 6-1.
"But I am excited to be back - hopefully it will be a positive week for me".
"To play at home always is fantastic", Nadal said after the match.
Sock and Harrison failed to break serve until the fourth set yet managed to see off doubles specialists Sander Gille and Joran Vliegen 5-7 7-6 (1) 7-6 (3) 6-4 to wrap up the tie in the fewest possible matches for the Americans.
Manu Bhaker, Punam Yadav win gold at CWG 2018
England's Sarah Davies took silver with 217 kg, while Apolonia Vaivai (216 kg) got bronze. Punam lifted 98 kg in her second attempt but Vaivai maintained the lead with 100 kg.
"I didn't even know if I really touched him on the shoulder".
Chardy, a surprise selection ahead of Adrian Mannarino, the world 25, suffered his first Davis Cup defeat in six matches. "I am playing not just for me but also for Italy".
The United States are at home to Belgium in Nashville in the other quarterfinal, with John Isner due to take on Joris de Loore in the opening singles rubber at 21.00 GMT.
Croatia also made it into the last four as Australian Open runner-up, Marin Cilic, crushed Kazakhstan's Mikhail Kukushkin 6-1 6-1 6-1 to seal their tie 3-1. Spain has won the Davis Cup four times with Nadal, in 2004, 2008, 2009 and 2011.
In Varazdin, Ivan Dodig and Nikola Mektic overcame Kazakhstan's Timur Khabibulin and Aleksandr Nedovyesov 6-7 (2) 6-4 6-4 6-2 to hand hosts Croatia a 2-1 lead.
The German pair edged the Spanish team in a thrilling five-setter 6-3 6-4 3-6 6-7 (4) 7-5.
Croatia will meet the United States in the semis in September following Jack Sock and Ryan Harrison's doubles win against Belgium's Sander Gille and Joran Vliegen on Saturday which gave the US a 3-0 win.
France, the 10-time winners, have two top 30 players in Lucas Pouille, ranked at 11, and Adrian Mannarino, the world 25.