For the first time in a decade, the top two women’s seeds at the China Open have failed to make it beyond the third round after Aryna Sabalenka suffered a shock loss on Sunday.

The world No.2 was brushed aside 6-3, 6-4 by Nikola Bartunkova, who has become only the second player to have beaten Sabalenka on a hardcourt this season whilst ranked outside the world’s top 20. Sabalenka was broken three times during the match but still won more than half of her service points (57%).

It is not the first time the four-time Grand Slam champion has been troubled by the Czech on the Tour. In their other meeting earlier this year, she was forced to battle back from a set down to defeat Bartunkova when they met on grass at the Berlin Open.

“First of all, I focused on myself, to be calm,” Bartunkova said of her win in China. “And Aryna, she’s great, she’s a legend, she’s a Grand Slam champion. So, yeah, I’m really happy that I won the match.”

It is only the second time in her career that 20-year-old Bartunkova has beaten a top-10 player. Her first was over Belinda Bencic at the Australian Open earlier this year.

“I’m not a girl who celebrates too much,” she said. “I’m trying to be focused because I’m still in the tournament. Today is doubles, so that’s my plan.”

Sabalenka’s exit comes a day after Elena Rybakina was stunned in the second round. Playing her first Tour-level match as world No.1, the Kazakh fell 3-6, 6-4, 6-3 to Alina Charaeva. Charaeva was playing a top-20 player for the first time in her career and is the first player representing Armenian to beat a world No. 1 since the WTA rankings were first published in 1975.

“I think it’s just about believing,” said Charaeva.

“I played a lot of matches lately, three-set matches. Honestly, always first set down. It’s kind of like, Okay, keep trying to turn around, keep fighting.”

Despite her loss, Rybakina still leads Sabalenka by more than 2000 points in the standings.