(Reuters) - Former world number one Victoria Azarenka's return from maternity leave was cut short by young Croatian Ana Konjuh at the Mallorca Open on Thursday.
The Belarusian, who saved match points in her first-round victory against Japan's Risa Ozaki, went down 6-1 6-3 to the seventh seed on the grasscourts at Santa Ponsa.
Konjuh, 19, dominated from the start and Azarenka had no answer to the depth and power of her opponent.
"I know Azarenka is coming back, but it's always tough to play against her," said Konjuh, who did not allow Azarenka a point until the third game of the match.
"She's one of the best players in the world.
"I was motivated for sure, and I'm really glad that I could play so well today and win."
Konjuh will face Anastasija Sevastova in the quarter-finals.
Italian Roberta Vinci also reached the last eight with a 6-4 5-7 6-2 win over Belgium's Kirsten Flipkens.
Defending champion Caroline Garcia's match against Jana Cepelova was suspended at 2-2 in the third set as the light faded.
Reporting by Martyn Herman, editing by Ed Osmond