LYON, France - Seventh-seeded Paula Badosa of Spain beat fourth-seeded Kristina Mladenovic of France 7-5, 6-7 (5), 6-2 in an error-strewn match to reach the Lyon Open semifinals on Friday.
Neither player looked comfortable on serve, combining for 21 double faults and 15 service breaks at the indoor tournament.
Badosa next faces 18-year-old Clara Tauson of Denmark, who continued her fine form by beating Camila Giorgi of Italy 6-3, 6-1.
Tauson had six aces and did not face a break point, also breaking Giorgi's serve five times in a dominant display.
The 139th-ranked Tauson, a former Australian Open junior champion, knocked out top-seeded Ekaterina Alexandrova in the first round.
She and Badosa are both looking to win their first WTA titles.
Second-seeded Fiona Ferro joined them in the last four in her bid for a third career title.
Ferro rallied to beat unseeded 19-year-old Clara Burel 2-6, 6-1, 6-3 in an all-French match where they dropped serve 12 times between them.
She next plays play Swiss player Viktorija Golubic, who beat unseeded Belgian player Greet Minnen 6-3, 7-6 (0).
Golubic, a qualifier ranked 130th, is seeking her second career title.