Australia's top-ranked player Samantha Stosur has set up a semi-final showdown with former world No.1 Jelena Jankovic at the BNP Paribas Open at Indian Wells.
The eighth seed moved into the last four with a 6-3 7-6 (9-7) win over 28th-seeded Spaniard Maria Jose Martinez Sanchez.
Stosur, who will break into the world's top 10 when the new rankings are released on Monday, was pushed all the way by her opponent in a keenly contested encounter, forcing the only break of service in the opening set before trading breaks in the second on her way to sealing the match on the tie-breaker.
Stosur, who beat defending champion Vera Zvonareva in the fourth round, is yet to drop a set on her way to the semi-finals.
Only nine Australian women have been ranked in the top 10 since computer rankings were introduced in 1975.
And only three of those have reached the milestone since 1980 - Jelena Dokic (who went to No.4), Alicia Molik (No.8) and now Stosur.
Earlier, Jankovic was made to work hard for a 6-4 6-4 victory over Alisa Kleybanova.
The Serb believes she is getting back to something approaching her best form. She is bidding to reach her first final since October, and prior to this week had failed to reach the quarter-finals at each of her last four tournaments.
Her run of poor form has been little in evidence at Indian Wells, however, and Jankovic admits she is hopeful the good times can continue.
"I think every win that I'm getting gives me a lot of confidence," said Jankovic.
"I feel that I'm coming back, and my game is getting better and better. It gives me more motivation. I feel like I can work much harder."
"I know what I need to work on just to get better as a player in general. So I'm just happy that I'm doing well here in this tournament, and I hope that I can keep it going."
Jankovic was rarely troubled and was broken only once as she saw off the plucky challenge of the 20-year-old Kleybanova, seeded 23rd.
Jankovic had won their previous meeting this season, in her country's Fed Cup tie against Russia, but Kleybanova went into the clash able to draw on the confidence of two victories over her more illustrious opponent last year.
The youngster had a first-serve percentage of 83 in the first set and forced four break points, but she paid for her failure to convert any of them as Jankovic took her only opportunity - and with it the set.
Jankovic was dominant on her own serve throughout both sets, and two breaks to Kleybanova's one earned her the second and a place in the last eight.
"I'm really happy that I got so far this week," said Kleybanova, who upset two-time champion Kim Clijsters in the third round.
"It's been really long, tough matches for me. I think the most important thing is that I've been really fighting a lot, and I played some good matches here."
Second seed Caroline Wozniacki of Denmark and Agnieszka Radwanska, the fifth seed from Poland, will meet in the other semi-final.