Rafael Nadal and Nick Kyrgios set up a blockbuster quarter-final showdown at Indian Wells after the Spaniard extended his perfect start to the season and the Australian received a walkover on Wednesday.
Nadal, who has won his first three tournaments this season including a record-setting 21st Grand Slam title at the Australian Open, moved to 18-0 for the year with a 7-6, 7-6 victory over American Reilly Opelka at the Masters 1000 event in California.
As expected against one of the ATP Tour's biggest servers, Nadal was faced with a barrage of aces in a match of fine margins which comprised just one break of serve each in the second set.
"I managed it so-so," he said of Opelka's serve, which the Spaniard stood as far back in the court as possible to receive. "I don't know if the cameras can follow me like 10 metres behind the baseline."
Nadal, aiming for a fourth Indian Wells title, became just the second player to start a season 18-0 since the ATP Tour launched in 1990. Novak Djokovic has done it twice, starting 41-0 in 2011 and 26-0 in 2020.
The Spaniard will face Kyrgios, who advanced on a walkover when Jannik Sinner withdrew due to illness, on Thursday. Nadal leads the head-to-head 5-3 and the two players have contested several thrilling matches over the years, including the first back in 2014 when Kyrgios announced himself on the world stage with a four-set victory at Wimbledon.
Nadal was followed into the quarter-finals by 18-year-old compatriot Carlos Alcaraz, who notched another breakthrough with a 7-5, 6-1 victory over 35-year-old Gael Monfils of France.
Alcaraz, into his first Masters 1000 quarter-final, is the youngest Indian Wells ATP quarter-finalist since 17-year-old Michael Chang in 1989. The winner of the title in Rio de Janeiro last month, Alcaraz gradually ramped up the pressure with a powerful ground game, converting his third break chance in the opening set with a forehand winner.
He didn't face a break point in the match, and gained an early edge in the second set with a deft drop shot that caught Monfils flat-footed behind the baseline.
Monfils, who captured a title in Adelaide in January, had upset world No 1 Daniil Medvedev in the third round, but his tournament ended with a whimper as he was broken for the fourth time of the night in the final game. Should they both advance Alcaraz would meet Nadal in the semi-finals.
"It would be amazing, but first I have to win quarter-finals," said Alcaraz, who next faces defending champion Cameron Norrie.
Norrie quashed a second-set rally bid from rising US talent Jenson Brooksby, who took a 3-0 lead in the second set only for Norrie to charge back to win 6-2, 6-4.
In other matches, Serbia's 61st-ranked Miomir Kecmanovic shocked sixth-ranked Matteo Berrettini 6-3, 6-7, 6-4 to book a quarter-final clash with American Taylor Fritz, who edged Australian Alex de Minaur 3-6, 6-4, 7-6.
Seventh-seeded Andrey Rublev, chasing a third successive title following triumphs in Marseille and Dubai, made it safely through, beating Poland's Hubert Hurkacz 7-6, 6-4 to set up a clash with Bulgarian Grigor Dimitrov – a 6-3, 7-6 winner over American John Isner.
In women's action, former world No 1 Simona Halep and third-seeded Ita Swiatek booked a semi-final showdown with a pair of lopsided victories.
Romania's Halep, a two-time Grand Slam champion and winner at Indian Wells in 2015, needed just 53 minutes to dispatch Croatian Petra Martic 6-1, 6-1.
Poland's Swiatek swept past American Madison Keys 6-1, 6-0 in 56 minutes. It was a welcome chance of pace for Swiatek, who had to rally from a set down in each of her first three matches.