Ash Barty's grip on the world number one ranking remains for now after winning in three sets against seventh seed Aryna Sabalenka in the Miami Open quarter-finals on Tuesday.
The 2019 Miami Open champion defeated Sabalenka 6-4 6-7 (5-7) 6-3 in humid conditions in South Florida to reach the last four, where the Australian will face fifth seed Elina Svitolina.
Svitolina won in the later match on Tuesday over Latvia's Anastasija Sevastova 6-3 6-2.
Barty, the 2019 French Open champion, did not drop her serve once against the Belarusian, saving seven break points throughout the match as she bids to retain her top ranking.
Barty is under threat from 2021 Australian Open winner Naomi Osaka for the number one ranking, with the Japanese also into the quarters.
The Australian will retain the top ranking by reaching the decider, regardless of second seed Osaka's results.
"It was a brilliant match today," Barty said in her on-court interview. "It was certainly the best level I’ve played for a long time and especially over a sustained period.
"Aryna really made me bring out my best stuff today. She’s an exceptional competitor."
Barty has now won 10 consecutive matches in Miami, dating back to her 2019 title with 2020's event cancelled due to the COVID-19 pandemic.
Ukraine's Svitolina, ranked fifth in the world, reached the Miami Open semi-finals for the first time with her win over the unseeded Sevastova.
"I've always wanted to play well here in Miami," said Svitolina, who made last year's French Open quarter-finals.
"It's one of the biggest tournaments and playing here is always amazing, so I'm really pleased with the performance tonight."