London - Rafael Nadal insisted on Tuesday that plans by Wimbledon to introduce a 25-second shot-clock will kill off the sport's capacity for epic Grand Slam confrontations.
The US Open will have a shot clock for this year's tournament with Wimbledon poised to follow suit.
World number one Nadal is routinely warned for slow play between points.
However, he believes players need time to compose themselves between points and to ponder tactics over five sets.
"If you want to see a quick game without thinking, well done," said Nadal.
"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 it is only about the business, so... I can't support this because I don't feel the matches that stay for the history of our sport went that quick."
Nadal has been involved in epic confrontations down the years as he amassed 17 Grand Slam titles.
He famously defeated Roger Federer in 2008 for the first of his two Wimbledon titles in a final which took the best part of five hours and ended in near-darkness.
In 2012, he lost the longest final at a major to Novak Djokovic in Australia, a five-setter which stretched to five hours and 53 minutes.
"I don't remember any emotional match that the total time was two hours," added the 32-year-old Nadal.
"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."
Despite his objections, the All England Club insist that a shot clock is on the agenda.
"There's a general feeling that we should speed up when a match begins and ends," said the tournament's chief executive Richard Lewis.
"The shot clock isn't a rule change, that's just something visible."
Nadal had no cause to worry about getting caught up in a marathon match on Tuesday as he opened his Wimbledon campaign with a 6-3, 6-3, 6-2 win over Israel's Dudi Sela, the world 127.
Fresh from an 11th French Open title, Nadal was playing on grass for the first time this season.
But there was no lack of competitive edge from the 2008 and 2010 champion who comfortably avoided being beaten at the tournament by a player ranked outside the top 100 for what would have been the fifth time in his last six visits.
"I had a long clay court season, a lot of matches," said Nadal as he explained why he sat out the grass court build-up to Wimbledon.
"After playing the final of Roland Garros and playing so many matches on clay, for my knees, the drastic changes are not good.
"So we decided to stop a couple of days, then to start step by step on grass. I did the same last year."
Next up for Nadal is Kazakhstan's Mikhail Kukushkin as the world number one looks to take another step to getting past the last 16 for the first time since 2011 when he was runner-up to Djokovic.
Meanwhile, Djokovic also weighed in on the shot clock debate, claiming the full opinion of the players has yet to be sought.
"I understand what they are trying to do with the shot clock," said Djokovic after making the second round with a 6-3, 6-1, 6-2 win over Tennys Sandgren.
"Everybody is trying to get this new generation of people and the attention span is not maybe as it used to be, except if you're a real, real tennis fan.
"But it has to be in line with the respect towards the tradition of the game."
Wimbledon results on Tuesday, the second day of the 2018 championships (x denotes seeded player):
Radu Albot (MDA) bt Pablo Carreno Busta (ESP x20) 3-6, 6-0, 6-7 (5/7), 6-2, 6-1
Marcos Baghdatis (CYP) bt Dominic Thiem (AUT x7) 6-4, 7-5, 2-0 - retired
Karen Khachanov (RUS) bt David Ferrer (ESP) 6-1, 7-6 (7/3), 3-6, 7-5
Julien Benneteau (FRA) bt Marton Fucsovics (HUN) 7-5, 7-5, 6-3
Frances Tiafoe (USA) bt Fernando Verdasco (ESP x30) 7-6 (8/6), 7-6 (7/5), 3-6, 6-3
Kyle Edmund (GBR x21) bt Alex Bolt (AUS) 6-2, 6-3, 7-5
Bradley Klahn (USA) bt Yuichi Sugita (JPN) 2-6, 7-6 (8/6), 6-2, 6-2
Horacio Zeballos (ARG) bt Guido Andreozzi (ARG) 4-6, 7-6 (7/1), 6-4, 6-4
Novak Djokovic (SRB x12) bt Tennys Sandgren (USA) 6-3, 6-1, 6-2
Nick Kyrgios (AUS x15) bt Denis Istomin (UZB) 7-6 (7/3), 7-6 (7/4), 6-7 (5/7), 6-3
Robin Haase (NED) bt Marius Copil (ROU) 7-6 (7/0), 7-5, 4-6, 7-6 (7/4)
Bernard Tomic (AUS) bt Hubert Hurkacz (POL) 6-4, 6-2, 7-6 (7/2)
Kei Nishikori (JPN x24) bt Christian Harrison (USA) 6-2, 4-6, 7-6 (7/3), 6-2
Damir Dzumhur (BIH x27) bt Maximilian Marterer (GER) 6-3, 6-2, 6-4
Ernests Gulbis (LAT) bt Jay Clarke (GBR) 4-6, 6-3, 7-6 (7/3), 3-6, 6-4
Taylor Fritz (USA) bt Lorenzo Sonego (ITA) 3-6, 6-3, 6-2, 6-2
Alexander Zverev (GER x4) bt James Duckworth (AUS) 7-5, 6-2, 6-0
Juan Martin Del Potro (ARG x5) bt Peter Gojowczyk (GER) 6-3, 6-4, 6-3
Feliciano Lopez (ESP) bt Federico Delbonis (ARG) 6-3, 6-4, 6-2
Benoit Paire (FRA) bt Jason Jung (TPE) 7-5, 7-6 (7/1), 6-4
Matteo Berrettini (ITA) bt Jack Sock (USA x18) 6-7 (5/7), 6-7 (3/7), 6-4, 7-5, 6-2
Gilles Simon (FRA) bt Nikoloz Basilashvili (GEO) 6-1, 7-6 (7/5), 6-1
Stephane Robert (FRA) bt Albert Ramos (ESP) 7-6 (7/5), 6-2, 6-1
Matthew Ebden (AUS) bt David Goffin (BEL x10) 6-4, 6-3, 6-4
Diego Schwartzman (ARG x14) bt Mirza Basic (BIH) 6-3, 6-2, 6-1
Jiri Vesely (CZE) bt Florian Mayer (GER) 7-6 (7/3), 6-4, 4-6, 6-1
Simone Bolelli (ITA) bt Pablo Cuevas (URU) 7-6 (7/5), 7-6 (8/6), 6-1
Fabio Fognini (ITA x19) bt Taro Daniel (JPN) 3-6, 6-3, 6-3, 6-3
Alex De Minaur (AUS) bt Marco Cecchinato (ITA x29) 6-4, 6-7 (6/8), 7-6 (7/5), 6-4
Pierre-Hugues Herbert (FRA) bt Mischa Zverev (GER) 6-4, 6-3, 6-4
Mikhail Kukushkin (KAZ) bt Vasek Pospisil (CAN) 6-4, 3-6, 6-2, 6-3
Rafael Nadal (ESP x2) bt Dudi Sela (ISR) 6-3, 6-3, 6-2
Simona Halep (ROU x1) bt Kurumi Nara (JPN) 6-2, 6-4
Zheng Saisai (CHN) bt Wang Qiang (CHN) 6-3, 4-6, 6-1
Lara Arruabarrena (ESP) bt Ana Bogdan (ROM) 6-1, 3-6, 8-6
Hsieh Su-Wei (TPE) bt Anastasia Pavlyuchenkova (RUS x30) 6-4, 4-6, 6-3
Johanna Konta (GBR x22) bt Natalia Vikhlyantseva (RUS) 7-5, 7-6 (9/7)
Dominika Cibulkova (SVK) bt Alize Cornet (FRA) 7-6 (7/3), 6-1
Elise Mertens (BEL x15) bt Danielle Collins (USA) 6-3, 6-2
Sofia Kenin (USA) bt Maria Sakkari (GRE) 6-4, 1-6, 6-1
Daria Gavrilova (AUS x26) bt Caroline Dolehide (USA) 6-2, 6-3
Samantha Stosur (AUS) bt Peng Shuai (CHN) 6-4, 7-5
Taylor Townsend (USA) bt Pauline Parmentier (FRA) 6-2, 6-4
Aliaksandra Sasnovich (BLR) bt Petra Kvitova (CZE x8) 6-4, 4-6, 6-0
Garbie Muguruza (ESP x3) bt Naomi Broady (GBR) 6-2, 7-5
Alison Van Uytvanck (BEL) bt Polona Hercog (SLO) 6-2, 6-2
Jennifer Brady (USA) bt Kateryna Kozlova (UKR) 6-2, 6-7 (4/7), 6-2
Anett Kontaveit (EST x28) bt Denisa Allertov (CZE) 6-2, 6-2
Ashleigh Barty (AUS x17) bt Stefanie Vogele (SUI) 7-5, 6-3
Eugenie Bouchard (CAN) bt Gabriella Taylor (GBR) 6-0, 4-6, 6-3
Angelique Kerber (GER x11) bt Vera Zvonareva (RUS) 7-5, 6-3
Claire Liu (USA) bt Ana Konjuh (CRO) 6-2, 6-7 (2/7), 6-3
Katie Boulter (GBR) bt Vernica Cepede (PAR) 6-4, 5-7, 6-4
Naomi Osaka (JPN x18) bt Monica Niculescu (ROU) 6-4, 6-1
Carla Suarez Navarro (ESP x27) bt Carina Witthoeft (GER) 6-2, 6-4
Sara Sorribes (ESP) bt Kaia Kanepi (EST) 7-6 (7/5), 6-1
Alison Riske (USA) bt Mariana Duque (COL) 6-1, 6-1
Belinda Bencic (SUI) bt Caroline Garcia (FRA x6) 7-6 (7/2), 6-3
Vera Lapko (BLR) bt Christina McHale (USA) 5-7, 7-5, 7-5
Vitalia Diatchenko (RUS) bt Maria Sharapova (RUS x24) 6-7 (3/7), 7-6 (7/3), 6-4