Roger Federer and Rafael Nadal will face each other for the first time since 2017 in the semi-finals at Indian Wells after winning their respective quarter-finals on Friday.
Swiss fourth seed Federer, 37, eased past Poland’s Hubert Hurkacz 6-4 6-4.
Spanish second seed Nadal, 32, required treatment on his right knee during a tough 7-6 (7-2) 7-6 (7-2) victory over Russia’s Karen Khachanov.
Nadal said he “hopefully” will be ready for Saturday’s semi-final.
“I will try my best to recover – these are the matches I want to play,” said the 17-time Grand Slam Champion.
“To play against my biggest rival at the later stages of our careers and to keep competing against each other is great.”
The two greats last played in the final of the Shanghai Masters in October 2017, when Federer won in straight sets.
The 20-time Grand Slam champion has won each of their last five matches but Nadal leads 23-15 in their head-to-head record.
“I don’t think those matches matter that much, to be honest,” said Federer, who is yet to drop a set in this year’s tournament.
“A lot of time has gone by, unfortunately maybe for the rivalry, for us, or for me. It’s always better to keep on playing against him.
“The fans are maybe more excited about us playing than me as I’ve always got to be focused on my own game.
“But it always brings extra energy into the stadium and for the both of us.”
‘I was having a tough time’
Federer is chasing a record sixth Indian Wells title – he is tied with Novak Djokovic on five – while Nadal is looking for his fourth.
The other semi-final in California sees Austrian seventh seed Dominic Thiem face Canada’s 13th seed Milos Raonic.
World number four Federer broke Hurkacz, 22, in the fifth game of the match before doing so again in the third game of the second set and saving both break points on his own serve to win in one hour 13 minutes.
Nadal had a far more difficult tie against 12th seed Khachanov, needing a medical time out after the third game of the second set in which tape was applied under his right knee.
The world number two looked in discomfort but saved a set point to avoid being taken to a decider before impressing again in the tie breaker to secure victory in two hours 16 minutes.
“I was having a tough time against a very, very tough opponent,” said Nadal.
“I managed to come back and had chances but he served huge, then I had some troubles with the knee but I was able to fight and find a way.”
BBC tennis correspondent Russell Fuller at Indian Wells
A physio running onto court to apply strapping to Nadal’s right knee is all too familiar, but remains a very sorry sight.
Nadal has shown before that he can absorb pain in the short term, and this was the first time he has felt discomfort this fortnight.
The same knee also needed treatment against Khachanov in the third round of last year’s US Open. But Nadal was able to win that gruelling match and then two further rounds, including a near five-hour victory over Dominic Thiem in the quarter-finals.
However, he had to pull out in the semi-finals – to cap a year of immense frustration in which he was able to complete only one hard-court tournament.
Nadal’s participation in next week’s Miami Masters must now be in some doubt, but let’s just hope his knee can at least see him through the weekend.