Angelique Kerber gained a measure of revenge for her Olympic defeat to Monica Puig by knocking the Puerto Rican out of the Dubai Tennis Championships after Agnieszka Radwanska suffered a shock third-round defeat to teenager CiCi Bellis.
Kerber enjoyed a golden 2016, but the world number two had to settle for a silver medal in Rio when Puig defeated her in the final last August.
It was the powerful German who prevailed in their first meeting since that showdown in Brazil, winning 6-2 6-3 on Wednesday to set up a quarter-final against Ana Konjuh - who sent eighth seed Elena Vesnina packing.
Kerber has been feeling pain in her right knee, but the top seed made just 12 unforced errors and denied Puig a solitary break to take another step towards a tournament win that would put her back above Serena Williams at the top of the rankings.
There was no upturn in fortunes for Radwanska as the fourth seed suffered a surprise 6-4 2-6 6-2 loss to 17-year-old outsider Bellis.
Radwanska was in need of a confidence boost after early exits at the Australian Open and Qatar Open, but world number 70 Bellis claimed the biggest scalp of her career.
Caroline Wozniacki will be Bellis' opponent in the last eight after the in-form 10th seed defeated Kateryna Bondarenko 3-6 6-2 6-3, while Elina Svitolina, Lauren Davis, Anastasija Sevastova and Wang Qiang also advanced.
Second seed Lucie Safarova coasted into the quarter-finals of the Hungarian Ladies Open with a 6-2 6-1 hammering of Su-Wei Hsieh after qualifier Aliaksandra Sasnovich stunned sixth seed Pauline Parmentier 7-6 (7-3) 6-4.
Julia Goerges and Annika Beck were also second-round winners, while Timea Babos beat Ipek Soylu in round one before fourth seed Sorana Cirstea fell at the first hurdle to Carina Witthoeft.