STRASBOURG, France - Dominika Cibulkova lost her first five matches to rival Samantha Stosur, but the Slovak continued chipping away at that head-to-head on Thursday, knocking out the 2017 Internationaux de Strasbourg champion, 6-4, 6-3, to advance into her second semifinal of the season.

The former World No.4 got her first win over the 2011 US Open champion last year at the Qatar Total Open, and though Stosur had won all three of their previous matches on clay, it was Cibulkova who got the early advantage on Court Patrice Dominguez, racing out to a 5-2 lead before ultimately serving it out on her fifth set point.

A French Open finalist back in 2010, Stosur won a rematch of last year's Strasbourg final over Gavrilova in the previous round. The veteran nonetheless dropped serve to start the second set and though she tried to keep things close, the Slovak ultimately proved too strong as she broke once more to secure victory after 93 minutes on court.

It was a nearly flawless display from Cibulkova, hitting 21 winners to 10 unforced errors while maintaining a solid 67% first serve percentage, and the former BNP Paribas WTA Finals Singapore presented by SC Global champion is yet to drop a set in Strasbourg.

Standing between the 2009 French Open semifinalist and a second final of the year is No.4 seed Mihaela Buzarnescu, who swept past Hsieh Su-Wei, 6-0, 6-3. Buzarnescu is slated to be seeded at her first-ever major tournament at next week's French Open, having already reached two WTA finals in 2018, including the J&T Banka Prague Open at the start of the clay court season.