Top seed Carlos Alcaraz fended off tenacious Tallon Griekspoor 7-6, 6-3 on Monday to reach the fourth round at Indian Wells, but former world No 1 Andy Murray was sent crashing out by fellow Brit Jack Draper.
Alcaraz, 19, had a testing time breaking through against his determined Dutch foe, who had won their only prior hard court meeting.
The Spanish world No 2, who will return to the top ranking by winning the title in California, didn't face a break point in the first set, nor could he convert either of his two. A strong start in the tiebreaker proved the difference, Alcaraz locking up the set with a forehand winner on his second set point.
Alcaraz rolled from there, breaking Griekspoor in the second game on the way to a 3-0 lead in the second set.
"It was a really tough match," Alcaraz said of his 100th ATP Tour match win. "Tallon is playing great, I had to be really focused. Of course playing with a lot of wind like today is also tough.
"I had chances at the beginning of the first set, I didn't take it. The second set, I took my chances that I had in the beginning and thanks to that I was able to play more relaxed."
Alcaraz will face Britain's Draper for a place in the quarter-finals after the British world No 56 overcame Murray 7-6, 6-2.
In other men's action, defending champion Taylor Fritz cruised past Argentina's Sebastian Baez 6-1, 6-2, and three-time Grand Slam champion Stan Wawrinka, 37, beat 19-year-old seventh seed Holger Rune 6-2, 6-7, 7-5.
A former world No 3 now ranked 100th, Wawrinka avenged a first-round defeat to the Dane at the Paris Masters in November, where Rune saved three match points to launch his run to a first Masters title.
Murray, 35 and trying to grind his way back after hip replacement surgery, couldn't pull off a similar feat against his 21-year-old compatriot Draper.
Draper led the first set 3-1 but was broken at love as he served for the set at 5-4. He had to save a set point with an ace but never trailed in the tiebreaker. Draper won the last four games to win his first meeting with his childhood hero.
"I've looked up to Andy since I was so young," said Draper, who will climb above Murray in the world rankings to become the third-highest ranked British player behind Cameron Norrie and Dan Evans.
"I watched him win Wimbledon for the first time in 2013. He's a really special person, a great champion, great human being and I'm privileged to play against him on this court."