Mihaela Buzarnescu dumped Elina Svitolina out of the Birmingham Classic, while top seed Caroline Garcia was beaten at the Mallorca Open on Friday.
Svitolina was the highest ranked player in the quarter-final draw in Birmingham, with Garbine Muguruza knocked out earlier in the week, but she too fell by the wayside.
Buzarnescu defeated Svitolina at the French Open and she came out on top in a second meeting in a matter of weeks, triumphing 6-3 6-2.
"I didn't go on the court thinking I played her three weeks ago," Buzarnescu said. "She's an amazing player, so young and so many achievements until now and so many to come.
"I just tried to go on the court, play my own game and focus on each point and take it as an ordinary match."
Buzarnescu moves into her first WTA Premier-level semi-final, where she will face defending champion Petra Kvitova, who breezed past Julia Goerges 6-1 6-4.
Barbora Strycova and Magdalena Rybarikova make up the last-four draw, Lesia Tsurenko's retirement handing the former victory while Dalila Jakupovic lost to the latter.
In Mallorca, Garcia went down 6-3 6-3 to Sofia Kenin, with Lucie Safarova, another seed, also knocked out by Tatjana Maria.
Teenager Kenin will now play the first WTA Tour semi-final of her career.
"I'm very happy. [Garcia] is a great player," she said. "It was a really tough match and I knew I had to fight until the end."
Alison Riske was defeated by Sam Stosur, and third seed Anastasija Sevastova came from behind to get past Ajla Tomljanovic 3-6 6-3 6-1.
|Deschamps praises Griezmann for Giroud gesture|
|Warriors star Curry improving, still out at least three more games|
|Chile 4 Honduras 1: Sanchez, Vidal shine for La Roja|
|Argentina 2 Mexico 0: Icardi, Dybala score first international goals|
|Mickelson calls Tiger the greatest of all time|
|Durant fined $25,000 for using inappropriate language|
|Fizdale isn´t concerned about Knicks´ losing streak|
|No particular concern for Mbappe – Deschamps|
|PSG team-mate Choupo-Moting hopes Neymar injury is not serious|
|McLeish marvels at stylish Scotland´s promotion success|
|Draw proves Poland can play well without Lewandowski – Brzeczek|
|Giggs: Wales let themselves down|
|Sarachan ´moved USA forward´ in interim spell|
|Mickelson lays $200,000 bet with Woods for first hole|
|Dolphins QB Tannehill to start against Colts|
|Murcia edge out Banvit, Bonn crush Opava|
|Neymar injury not serious, says doctor|
|Mancini: Italy ahead of schedule|
|France 1 Uruguay 0: Giroud hits the spot after Mbappe injury blow|
|Portugal 1 Poland 1: Milik penalty salvages precious point as Danilo sees red|
|Italy 1 United States 0: Politano snatches late winner for Mancini´s men|
|Scotland 3 Israel 2: Forrest hat-trick seals Nations League promotion|
|Brazil 1 Cameroon 0: Richarlison fills Neymar´s boots as skipper suffers injury|
|France & PSG star Mbappe suffers shoulder injury|
|Albania 1 Wales 0: Gunter´s night spoiled by Balaj|
|Leeds and Manchester United to meet in friendly|
|Outspoken Smith leaves Cavaliers|
|PSG star Neymar injured for Brazil|
|Juventus midfielder Can back in training after surgery|
|Rams-Chiefs rollercoaster was the NFL´s modern-day masterpiece|
|Ronaldo an AC Milan target in 2017, confirms Fassone|
|Farah could get back on track at Tokyo Olympics|
|PSG still waiting on Alves and Kurzawa|
|Atalanta reject Gasperini to AC Milan speculation|
|Edmonton Oilers name Hitchcock new head coach|
|JR Smith on Cleveland Cavaliers: Tanking ´was always the plan´|
|Chester signs new Wakefield deal|
|F1 Raceweek: Countdown on to Alonso farewell|
|Rain disrupts Lorenzo´s Honda debut|
|VAR a possibility for Champions League knockout rounds|
|FFP vulnerable in areas, says UEFA president Ceferin|
|Sri Lanka draft in uncapped Peiris to replace Dananjaya|
|Coman back in Bayern training but Lewandowski has knee injury|
|Qalandars land De Villiers in PSL draft, Smith second pick|
|F1 changes helped less talented drivers on the grid - Alonso|
|Agnelli: No super league talks since 2015|
|I hope from now on it only gets better - Floersch update on horror crash|
|Calf injury rules Ashton out of Australia match|
|Halfpenny to miss South Africa clash|
|Hard for Lazio to hold on to Milinkovic-Savic, says Lotito|
|Australia´s next generation pay tribute to retiring Cahill|
|Bairstow pushing hard for Test recall|
|Cane eyes 2019 Super Rugby return after neck break|
|Van Dijk finds time to console referee during Dutch delight|
|Cahill sheds tear at end of phenomenal Australia career|
|WATCH: Pelicans coach Gentry interviews himself|
|Where does Chiefs-Rams classic rank among NFL´s highest-scoring matches?|
|Australia 3 Lebanon 0: Boyle bags brace on Cahill farewell|
|Guendouzi underlines desire to represent France|
|I might need a couple of drinks to relax after that! - Rams coach McVay|
|Juventus´ Alex Sandro has Premier League ambition|
|Ederson taking goalkeeping to another level, says City hero Weaver|
|Ceferin dismisses "super league" plans as fiction|
|Rams defeat Chiefs in one of the highest scoring games in NFL history|
|Kemba Walker leads Hornets to win over Celtics|
|Gomez praises ´top player´ Van Dijk, Stones|
|Cricket Australia to maintain Smith, Warner ball tampering bans|
|Brazil´s Tite encouraged by Neymar captaincy|
|Holmes set for NFL switch after Cronulla release|
|Dier encourages English youngsters to follow Sancho´s lead|