INDIAN WELLS: Rafael Nadal needed all he had to fend off Reilly Opelka at the ATP Indian Wells Masters, and he doesn't expect an easier ride from longtime rival Nick Kyrgios in the quarter-finals.
Kyrgios and Nadal have endured a sometimes bitter relationship on court.
In 2019, Nadal accused the Australian of "lacking respect" after Kyrgios won a stormy encounter in Mexico.
Kyrgios responded by claiming the Spanish world number two was "super-salty".
They met again at Wimbledon that year, when Nadal won but fumed after the Australian appeared to spear a ball directly at him.
In all they've met eight times, with Nadal coming out on top in five of those encounters.
"Nick is difficult in any conditions, no?" Nadal said Wednesday after booking the last-eight match-up with a 7-6 (7/3), 7-6 (7/5) victory over Opelka.
"When he's playing well and when he's excited and motivated he's one of the toughest opponents without a doubt."
Nadal battled two-plus hours to get past Opelka, the towering 2.11m self-described "servebot" who peppered the 21-time Grand Slam champion with serves routinely topping 140mph.
Kyrgios, meanwhile, advanced by a walkover when Jannik Sinner withdrew because of illness.
In addition to being less rested for Thursday's afternoon clash, Nadal acknowledged that he is feeling the left foot injury that brought his 2021 season to a premature end.
"I felt my foot a little bit on the second set," he said. "I was able to keep going, keep running til the end.
"(But) I am not in the moment to lie or to hide things ... today was a little bit worse than other days. Something can happen, we know that."
Nadal, who won a record-setting 21st Grand Slam title at the Australian Open in January and lifted the trophy in Acapulco last month, has now stretched his career-best season start to 18-0.
Whether he captures a fourth Indian Wells title or not, he has already opted out of next week's Miami Open, saying he'll take some time off and then start preparing for the claycourt season.
In the meantime, Nadal said, he prefers to focus not on his foot but on his next opponent, in this case Kyrgios.
"I am not thinking about the foot much," he said."I am just thinking about my tennis and my next opponent. If something happens, we need to accept it.
"Tomorrow going to be a tough match, but we are in quarter-finals of Indian Wells, Masters 1000. We can't expect another thing, no?"
Kyrgios, 26 and currently ranked 132nd in the world, is in the sixth Masters level quarter-final of his career and his first since Cincinnati in 2017.
He is playing is first tournament since capturing the 2022 Australian Open Men's doubles title in January with fellow Aussie Thanasi Kokkinakis.
The mercurial Australian has yet to drop a set this week, and toppled eighth-seeded Norwegian Casper Ruud 6-4, 6-4 in the third round.