Naomi Osaka bowed out of the Berlin Open after falling short in a three-set thriller against an inspired serving display from Zheng Qinwen.
The former world number one battled, but ultimately came up short for the second time in two weeks, enduring a 6-4 3-6 6-3 defeat.
The Japanese found herself a set down following a break point claimed in the fifth game by her opponent but rallied in the second to take the encounter to a deciding set.
However, Zheng, who served 10 aces in the final set, proved too powerful for Osaka to secure a second victory over the Japanese after two hours and 10 minutes at the Steffi Graf Stadium.
Zheng will play Katerina Siniakova in the last 16 on Wednesday, with either Jessica Pegula or Donna Vekic awaiting should she progress.
Data Debrief: Acing it
The victory for Zheng saw her serve 23 aces against Osaka, the highest tally in a single WTA match since Rebecca Marino vs Caroline Garcia in Guadalajara in 2022 (24).
Her success with her serving saw Zheng win 88 per cent of her first serve points, winning 44 of 50 during the match.