The emergence of a third young star to challenge the supremacy of Carlos Alcaraz and Jannik Sinner would push the duo's already scintillating rivalry to new heights, tennis great John McEnroe said.
Order of Play | Watch Live on DStv
Alcaraz and Sinner are coming off a French Open final for the ages and head into next week's Wimbledon having evenly split the last six majors between them.
"It's going to be an interesting time to see if there's another player or two who can break in with those two the way Novak (Djokovic) did when he was trying to get to the same level as Roger (Federer) and Rafa (Nadal)," McEnroe told reporters on Wednesday.
"It shows you what type of a player he was that he was able to do that. But right now, there's a void."
Djokovic, Federer and Nadal enjoyed a two-decade stranglehold on men's tennis and their era of dominance was made even richer by the three-sided nature of the rivalry.
In a Roland Garros showdown of unsurpassed quality, 22-year-old Alcaraz of Spain saved three successive match points to battle back from two sets down and beat the Italian in the longest French Open final in history.
Miami Open champion Jakub Mensik, 19, and 18-year-old Brazilian Joao Fonseca are two teenagers McEnroe could envision breaking into the Alcaraz-Sinner rivalry, as well as big-serving American Ben Shelton.
"One of those two guys or Ben would be my choice right now," said seven-time Grand Slam champion McEnroe.
"I think it would be important to get another guy or two to add to the mix. That would be really helpful."
McEnroe said the future of men's tennis is in great hands provided Alcaraz, who is seeking a hat-trick of Wimbledon titles next month, and world No 1 Sinner stay healthy.
"It was unheard of what we watched over the last 20 years and you can make the argument that what we're seeing now is even faster and different from what we saw even five years ago," he said.
"I can't wait to see what it's going to be like in 10 years, or five years even."