Daria Kasatkina saved two match points before knocking Johanna Konta out of the Dubai Tennis Championships and Jelena Ostapenko bowed out in the second round on Wednesday.
Seventh seed Konta won the opening set and had two opportunities to reach the quarter-finals in a second-set tie-break, but went down 4-6 7-6 (8-6) 6-2 to Russian Kasatkina.
Kasatkina lost the first two games of the second set, but was back on serve at 3-3 and hung in there in the breaker before grasping her first chance to level the match.
The unseeded 20-year-old won five games in a row to move into the last eight and will now come up against compatriot Elena Vesnina.
Vesnina claimed the scalp of fourth seed Ostapenko, the French Open champion losing 6-1 7-6 (8-6).
Ostapenko lost her first match in the Qatar Open last week after being given a bye into the second round and it was the same story in Dubai, where she was broken five times.
Former world number ones Angelique Kerber and Karolina Pliskova will meet in the quarter-finals after seeing off Sara Errani and Carla Suarez Navarro respectively.
Kerber eased to a 6-4 6-2 victory over the experienced Italian, while Pliskova came from a set down to defeat Suarez Navarro 5-7 6-2 6-4. Top seed Elina Svitolina, Garbine Muguruza, Caroline Garcia and Naomi Osaka also made it through.
Top seed Dominika Cibulkova eased into the second round of the Hungarian Ladies Open with a 6-3 6-3 win over Fanny Stollar.
Defending champion Timea Babos also made progress in Budapest, thrashing Tatjana Maria 6-1 6-0 and second seed Zhang Shuai beat Arina Rodionova 6-3 6-2.
Seeds Mihaela Buzarnescu and Aliaksandra Sasnovich were dumped out by Alison Van Uytvanck and Petra Martic respectively.
|Cardinals keep pace in wildcard race with win over Giants|
|Djokovic hits Federer, pair lose in doubles at Laver Cup|
|Nowitzki likely to come off bench for Mavericks in 21st season|
|Red Wings´ Green battling ´virus that attacked his liver´|
|They said I couldn´t score goals – Ibrahimovic hits back at early critics|
|Slater charged, set to miss Grand Final|
|Rose not changing approach alongside Woods|
|Woods ready to ´hang in there´ at East Lake|
|Shaqiri´s time will come at Liverpool – Klopp|
|Richarlison: I used to copy some of Neymar´s haircuts|
|Brady says Gordon is ´really eager to get in there´ despite limited practice|
|NBA changes clock-reset, ´clear path´ foul rules|
|Tigers´ Martinez will play final game on Saturday before retiring|
|Sanchez to start for Man United – Mourinho|
|Speight saves Ulster in thrilling Cheetahs draw|
|Simmonds at the double as Chiefs stay perfect|
|Woods, Rose share Tour Championship lead|
|Ice-cool Shoaib denies Afghanistan in final over|
|CAF Champions League Review: Wydad Casablanca out as TP Mazembe pay penalty|
|Eden inspires rout as Castleford book Wigan semi-final|
|Thiem & Wawrinka reach St. Petersburg semi-finals|
|No change to Aguero selection despite new contract, warns Guardiola|
|Woods and Rose share Tour Championship lead|
|Wigan Athletic 1 Bristol City 0: Three on the trot for improving Latics|
|Josh Rosen will play ´when time is right,´ Cardinals GM says|
|Eagles RBs Ajayi & Sproles out Sunday v Colts|
|Ronaldo looking forward after Champions League red card - Alex Sandro|
|Rangers fire manager Jeff Banister after four seasons|
|Inter captain Icardi can improve - Spalletti|
|Jadeja and Rohit shine as India maintain 100 per cent record|
|Fisher shares lead in Vilamoura after record-breaking 59|
|Messi the best I´ve seen - Lamela|
|Silva demands end to Gomes ´rumours´ and targets early October return|
|Milner over Pogba, says Souness|
|Brazil call up Malcom, drop Thiago Silva and Willian|
|Denly thought Test chance may never come|
|Benitez tells FA to examine Zaha red card comments|
|Bjorn unsure of future after Ryder Cup|
|Tebas still optimistic over Girona-Barcelona in Miami despite RFEF setback|
|Emery promises more chances for frustrated Leno|
|Cahill considering Chelsea departure in January|
|Kaepernick to receive Harvard´s highest honour in African, African-American studies|
|Defending champion Ostapenko dumped out of Korea Open|
|Mourinho is an inspiration - Nuno|
|Witty Wilson ´delighted´ to be praised for Fisher heroics while sitting on couch|
|Burns, Denly and Stone in England squad for Sri Lanka Tests|
|Aspas reveals interest from Real Madrid, Atletico|
|Arsenal´s Mkhitaryan a doubt for Everton match|
|Klopp demands Liverpool ´stay angry´ against Southampton|
|Long-serving Tabarez signs four-year Uruguay extension|
|Injured Mendy ruled out of Cardiff trip|
|Douglas Costa out up to a month with ankle & thigh injuries|
|Slater shrugs off Feki hit amid Grand Final suspension concerns|
|Crisis? What crisis? Klopp unconcerned by Salah form|
|I didn´t convince him, he decided for himself - Guardiola says thanks to Aguero|
|Leno frustrated by Arsenal bench role|
|Joshua almost 2st heavier than Povetkin for Wembley bout|
|From salvation to the record books - Fisher revels in European Tour´s first 59|
|Lahm says Germany best for Euro 2024 as UEFA publishes report|
|Lopetegui backs Modric over Ronaldo for individual prizes|
|Goretzka to start against former club Schalke, confirms Kovac|
|Fisher shoots first 59 in European Tour history|
|Simeone defends Ronaldo after controversial Champions League red|
|Slater sees Storm into Grand Final, awaits fate over ´shoulder charge´|
|Hogg to miss Scotland´s November Tests following ankle surgery|
|Osaka through as Azarenka and Garcia crash out|
|Burgess weighing up legal options after being cleared in Rabbitohs investigation|
|Uncapped Cottrell and Gordon named in Wallabies squad|
|He´s done fantastic work - Mourinho hails Wolves boss Nuno|
|Joshua v Povetkin: No need for fireworks on AJ´s Wembley return|