Jelena Ostapenko, Marketa Vondrousova headline intriguing Luxembourg semifinals

WATCH: Vondrousova was the last of the quarterfinalists into Luxembourg's final four, upsetting Elise Mertens in straight sets.

Marketa Vondrousova completed the 2021 BGL BNP Paribas Luxembourg Open semifinal line-up on Friday with a decisive win over No. 2 seed Elise Mertens, 7-5, 6-2.

The reigning Olympic silver medalist is seeded No. 5 in Luxembourg and is yet to drop a set at the WTA 250 event after ousting Mertens in one hour and 37 minutes on Center Court.

Luxembourg’s premier tennis tournament resumed action for the first time since 2019 earlier this week, having had to cancel the 2020 edition of the tournament due to COVID-19 concerns, and has already witnessed the emotional farewell of its country’s top-ranked player Mandy Minella.

An all-star quarterfinals day did much to raise the spirits of the Luxembourg crowd, who first watched 2019 champion Jelena Ostapenko edge past Alizé Cornet, 7-6 (6), 6-2. The No. 3-seeded Ostapenko improved her winning streak to 8-0 after riding the momentum from a tense tiebreaker into a more seamless second set.

The 2017 French Open champion will next face No. 7 seed Liudmila Samsonova after the surging Russian star scored the upset of the day over top seed Belinda Bencic, 6-1, 6-4.

Samsonova burst onto the scene earlier this year with a stunning triumph in Berlin, where she defeated Bencic in the final. Ranked at a career-high of No. 48, she broke the Tokyo Olympic champion three times to reach her second WTA semifinal of the season.

Vondrousova is a potential final opponent for either Ostapenko or Samsonova, provided the Czech gets past Danish teenager Clara Tauson; the only unseeded player left in the draw, Tauson knocked out Marie Bouzkova, 6-3, 6-2 to ease into her second career semifinal.

“I think I played a very solid match and I didn’t let her get a chance today. I’m very pleased and happy with the win,” she said after the match.

Tauson roared through the WTA 250 in Lyon to win her first title back in March, and has amassed a 9-1 record in her last three tournaments after winning a WTA 125K title in Chicago. Her only loss? To world No. 1 Ashleigh Barty at the US Open.

The 19-year-old will take on Vondrousova for the first time in singles, having fallen to the former French Open finalist in doubles last month in Chicago.

“I just hope I can go in and play a solid match tomorrow and see how far it goes,” Tauson said.