Stunned Zheng blames lack of warm-up for early Melbourne exit
China's Olympic champion nicknamed "Queen Wen" gave an unusually flat performance as she bowed out in round two in Melbourne.
She became flustered when she fell foul of the 25-second timer at a crucial moment in the second set before losing 7-6 (7/3), 6-3 to the world number 97.
Fifth seed Zheng was playing just her second match of 2025, saying "issues" after the season-ending WTA Tour Finals had prevented her playing in any warm-ups.
"For me there was no chance to play a tournament before the Australian Open this year because there were some issues in my body I didn't solve yet," she told reporters.
She did not elaborate on the nature of the problem.
Zheng also admitted that the shot-clock kerfuffle had "distracted" her.
At 2-2, 15-30 in the second set, Zheng received a second time violation which cost her a first serve.
She had a lengthy argument with the chair umpire, complaining that she could not see the shot clock, to no avail.
"The clock was on the side, so I couldn't see it if I bounce the ball," explained Zheng.
"So I don't know if I'm late or I'm early.
"I was so surprised to get that second (violation). Obviously that one really distracted me from the match."
Zheng completely fluffed the subsequent second serve and then double-faulted on break point to hand a crucial 3-1 advantage to Siegemund.
It led to a stunning defeat for the 22-year-old, who enjoyed a breakthrough 2024, beating then number one Iga Swiatek on her way to winning Olympic gold in Paris and claiming three WTA titles.
Zheng ended the year at a career-high world number five after claiming the Pan Pacific Open title in Tokyo.
She reached the championship match at the WTA Tour Finals in Riyadh, where she was edged only in a final-set tiebreak by Coco Gauff.
"I feel maybe today is not my day," said Zheng. "That's all I can say. It's tennis.".