Rafael Nadal, the 21-time grand slam winner, says the recently announced introduction of final-set tie-breaks across all grand slams will make the biggest impact at Wimbledon, rather than the French Open.

Tennis' Grand Slam Board announced this week that first-to-10 tie-breaks will be trialled across all grand slams with immediate effect, as a means of providing "greater consistency" to matches which go the distance.

Previously, each grand slam was free to adopt its own rules for deciding longer matches, with the Australian Open the only one to use first-to-10 tie-breaks at 6-6 in a deciding set.

Wimbledon, for example, used a first-to-seven tie-break to decide final sets which reached 12-12.

Speaking after dispatching Reilly Opelka in straight sets at the Indian Wells Masters, Nadal, who will look to add to his Australian Open triumph in the year's other three majors, explained he was not for or against the changes.

The 35-year-old also, however, predicted the alterations would have a bigger impact at Wimbledon than at the French Open, which he could win for a 14th time at Roland Garros in May.

"I don't care much, honestly!" said Nadal. "I am not in favour or not against, that's what they decided, and happy with it or not, I don't think I'm going to make a big difference.

"But I read that every [tournament] is going to have the same, and in some ways that's positive.

"I don't think at Roland Garros it will make a big impact. In my opinion the biggest impact is going to be at Wimbledon, [where] sometimes it's so difficult to break serve, so the matches become very long.

"I don't feel that for Roland Garros it will change a lot. Okay, [without the changes] it can be a few more games, but I don't think at Roland Garros you're normally going to go to 22-20. At Wimbledon, that can happen."

The longest men's singles match played at a grand slam, judged by the number of games played, came at Wimbledon in 2010, when John Isner beat Nicolas Mahut 6-4 3-6 6-7 (7-9) 7-6 (7-3) 70-68.

By contrast, the longest men's singles match in French Open history saw Fabrice Santoro beat fellow Frenchman Arnaud Clement 6-4 6-3 6-7 (5-7) 3-6 16-14, in 2004. 

After defeating Opelka in his round-of-16 tie at Indian Wells, Nadal will now face Australia's Nick Kyrgios for a place in the semi-finals.

Earlier in the week, the Spaniard became the first-ever player to reach 400 wins at Masters 1000 tournaments by beating Dan Evans in the last 32.