Zheng Qinwen is such a popular star in the professional tennis world that brands coveting the Chinese star's huge exposure have set sights on her opponent.

Halfway into her second round match against Laura Siegemund at the Australian Open, fans watching TV at home on Wednesday morning captured an intriguing tiny detail on the German veteran's attire — a newly-added logo of what apparently seemed a Chinese brand on the chest of her dress that wasn't there two days ago during her opening-round match.

Zheng's surging popularity, and the attention that comes with it, has made almost everything and everyone around her, and even against her in Wednesday's case, marketable to potential sponsors.

Yet, fame comes at a cost and the reigning Olympic champion learned it the hard way as Zheng suffered a major upset at the hands of Siegemund, who stunned the world No 5 with a 7-6 (3), 6-3 win at the John Cain Arena that put an abrupt end to Zheng's attempt of repeating her final run last year.

Zheng, who's had a breakout second half in 2024 anchored by an Olympic gold medal in Paris, admitted that she's not 100 percent opening the new season.

"I got some small issues (with my right elbow) after the WTA Finals. I was even discussing with my team if we have to come to play the Australian Open or not," Zheng, who lost to world No 1 Aryna Sabalenka in last year's final, confessed at the post-match news conference on Wednesday.

"I carried the pain with me at this tournament. I felt it sometimes in a shot, and to contain it, I had to cut short my practice sessions. So yes, it affected my game," said Zheng, who skipped all the warm-up tournaments before the season-opening major this year.

With her surprising defeat to last year's finalist, Siegemund, who entered this year's Australian Open at No 97, has won more than just the 70 ranking points and nearly $180,000 prize money for making into the third round at the Melbourne Park.

Little known in China before Wednesday, Siegemund now has made her presence felt in the emerging tennis market and has earned an endorsement deal, at least for a day, from a Chinese company.

"I knew I had to play more than my best tennis," Siegemund, who is expected to rise to top-80 with the victory over Zheng, said in her on-court interview.

"I had nothing to lose, so I just told myself to swing freely. (Zheng) is an amazing player, just one of the best players right now.

"But I know that I can play well and I just wanted to show that to myself and make it a tough fight."