World number one Iga Swiatek reached her 10th semi-final of the season on Friday by defeating American qualifier Caty McNally in straight sets at the Ostrava WTA tournament while Ons Jabeur lost to American Claire Liu in the quarterfinals of her home tournament in Monastir.

French and US Open champion Swiatek triumphed 6-4, 6-4 to take her 2022 record to 59 wins against just seven defeats.

The 21-year-old Pole is just one victory away from tying Caroline Wozniacki, the last player to win 60 matches in a single season in 2017.

“It was definitely physical – at the beginning of the second set I could feel my energy level went down a little bit,” said Swiatek, who fired 24 winners to McNally’s 18.

“I’m pretty happy I got it back again and I could use my experience in my important moments, because Caty played really well.”

Swiatek had won the 2018 French Open girls’ doubles title with McNally, who is ranked at 151.

“Tactically it was easier to prepare, because I know her game style. She’s playing differently to other players. But on the other hand, a lot of time has passed since we played last time. I knew she’d made progress and I had to be ready,” added the top seed.

Swiatek will face either wild card Tereza Martincova of the Czech Republic or Russia’s Ekaterina Alexandrova on Saturday for a place in the final.

Former French Open champion Barbora Krejcikova defeated 144th-ranked Alycia Parks 7-6 (9/7), 6-3 of the United States in her quarter-final.

The Czech will next face Kazakhstan’s reigning Wimbledon champion Elena Rybakina who unleashed 31 winners past Petra Kvitova in a 7-6 (7/5), 6-4 victory.

The win gave Rybakina a career-best 36th main-draw victory this season.

Jabeur loses at home

World number two Jabeur failed in her bid to land the first ever WTA tournament to be held in her homeland Tunisia when she lost 6-3, 4-6, 6-4 to Liu in Monastir on Friday.

Top seed Jabeur went into the quarter-finals in irrepressible form having dropped just nine games in her previous two matches against the American Ann Li then the Russian Evgeniya Rodina.

But she was handed a surprise defeat by Liu, ranked 71 places below her, who came into the tournament in good form. The 22-year-old from California reached the quarter-finals in Tokyo in mid-September and was a finalist in Rabat in May.

Liu broke Jabeur’s first service game and held on to that advantage to take the opening set.

The Tunisian favourite managed just 45 percent on her first serves but, in spite of further problems in the second, bounced back to level the match.

The errors continued in the third set - both players clocking 51 unforced errors in the match - with Liu edging the Wimbledon and US Open runner-up.

In the semi-finals, Liu will face Belgian Elise Mertens who needed two hours to wear down the 21-year-old Japanese player Moyuka Uchijima 6-0, 3-6, 6-4.

The other semi-final will pit Frenchwoman Alize Cornet against 12th ranked Russian Veronika Kudermetova.