The U.S. Open has decided to introduce a shot clock this year so that the 25 seconds allowed between points is strictly enforced and Wimbledon is likely to follow suit.
Former world number one Novak Djokovic later described that decision as "disrespectful" to the players.
Nadal, who has often fallen foul of the slow-play rule during his career, said he could not support the move.
"I'm 32. I don't know for how long I'm going to play. Hopefully for a long time. But is something that is not bothering me," the Spaniard said when asked for his opinion in his news conference after a 6-3 6-2 6-2 win over Sela which took less than two hours on Centre Court.
"In terms of the sport, depends. If you want to see a quick game without thinking, well done.
"If you want to keep playing in a sport that you need to think, you need to play with more tactics, you want to have long and good rallies, then of course you are going the wrong way.
"But seems like sometimes is only about the business, so... I can't support this, no. Because I don't feel the matches that stay for the history of our sport went that quick."
Nadal pointed to his epic four hour 48 minute Wimbledon final against Roger Federer in 2008 -- a match widely considered the best final ever played at the All England Club.
He said speeding up tennis could water down the drama, although in fact Grand Slams now allow 25 seconds between points rather than the 20 seconds of 10 years ago.
"I don't remember an emotional match that the total time of the match has been two hours," Nadal said.
"All the matches that have been important in the history of our sport have been four hours, five hours.
"To play these kind of matches you need time between points because you cannot play points in a row with long rallies, with emotional points, having only 25 seconds between points."
Djokovic, who has fought some incredibly lengthy duels against Nadal, also expressed his annoyance that the players had not been kept informed about the U.S. Open's decision to use shot clock later this year having trialed it in the qualifying tournament last year.
"Look, I'm not completely against it," the Serb said. "I feel like they should have reached out to players before they make an official decision, before they announce it.
"By not doing that, they show how respectful they are of us, which is unfortunate.
"I understand the whole mechanics behind it, the motives, I would say. But it has to be in line with the respect towards the tradition of the game."
(Reporting by Martyn Herman; editing by Ed Osmond)
