There has been talk of a rule change which would see some tournaments scrap the system in favour of shorter, best-of-three-set matches.
The searing heat at this year’s US Open has added weight to the claims of those who believe tennis clashes should be shorter to avoid energy-sapping matches taking too much out of the game’s best players.
Nadal’s quarter-final clash with Thiem lasted four hours and 49 minutes earlier this week and was decided by a fifth-set tie break.
But Darren Cahill, a former player and current coach of world No 1 Simona Halep, believes clashes like these are essential for epic Grand Slams tournaments.
“Best-of-five epitomises everything the game is about and separates the Grand Slams from what the men play on the regular tour,” he told USA TODAY Sports.
“You just have to watch the [Nadal-Thiem] match on Tuesday night and you’ll remember those matches for a lifetime.
“I’m a big supporter of best-of-five and I don’t think it’s going anywhere.
“When you look at some of the greatest matches throughout the course of history nearly all of them are best-of-five.”
Nadal faces Del Potro this evening in the US Open semi-final.
Speaking earlier this week, the Spaniard appeared to also support five set games.
“What is important about this match is the level of tennis, the dramatic match,” he said.
“When things happen like this, the atmosphere and the crowd become more special.
“People get involved.
A great match with great atmosphere.”
Nadal will be hoping to book his place in the US Open final this evening, where he will meet either Novak Djokovic or Kei Nishikori.