Andy Murray's latest comeback from a persistent hip issue ended prematurely on Wednesday when he was beaten 7-5, 6-2 by Russia's Daniil Medvedev in the second round of the Brisbane International.
Murray cut short his season last September after suffering pain in his hip following surgery earlier in the year that ruled him out of three of the four Grand Slam tournaments.
The 31-year-old had defeated local hope James Duckworth in his season opener on Tuesday but was comprehensively beaten by fourth seed Medvedev who fired 16 aces and lost only seven of his first-service points in the contest.
"I think he served extremely well, I didn't really get many chances on his service games," Murray, who won the tournament in both of his previous appearances in 2012 and 2013, said.
Medvedev next faces Canada's Milos Raonic who eased past Serbian qualifier Miomir Kecmanovic 6-3 7-6(2).
Jeremy Chardy rallied to beat holder Nick Kyrgios 6-7(5), 6-2, 6-3 to leave Alex De Minaur as the sole Australian man remaining in the draw after the 19-year-old beat Jordan Thompson 6-4, 6-2.
Grigor Dimitrov downed local favourite John Millman 6-3, 6-4 to set up a quarterfinal with Japan's Kei Nishikori.
In the women's competition, unseeded Anett Kontaveit upset double Wimbledon champion Petra Kvitova 7-5, 7-6(1) before paying tribute to fellow Estonian Kaia Kanepi who had claimed the Brisbane title in 2012.
Former champion Karolina Pliskova outclassed Marie Bouzkova 7-5, 6-2 to set up a clash with Ajla Tomljanovic who ended the run of Briton Johanna Konta winning 6-2, 7-6(2).
Defending champion Elina Svitolina crashed out at the hands of Belarusian Aliaksandra Sasnovich. In a replay of last year's final, Sasnovich reversed that result as she ousted Svitolina 6-4, 0-6, 6-3.
The Belarusian displayed some breathtaking shot-making in the first set before Svitolina stormed back in the second.
But Sasnovich continued to go for her shots and broke Svitolina twice in the third set to seal victory and book a quarterfinal against Croatian Donna Vekic.
Vekic continued her good form as she downed Dutchwoman Kiki Bertens in three sets 7-6 (7/5), 1-6, 7-5.
In Beijing, former world number one Maria Sharapova qualified for the quarterfinals of the Shenzhen WTA after struggling against China's great tennis hope Wang Xinyu, who was forced to retire from the match in pain.
The fifth-seed Russian was surprised early on by the power of her 17-year-old opponent, who took the final game of the first set 7-6 and broke in the second. But Wang Xinyu had to retire hurt, apparently after feeling pain in her thigh, while she was leading 5-2 in the second set.
In the next round, Sharapova takes on top-seed Belorussian Aryna Sabalenka, who had an easy win over Russian Ekaterina Alexandrova on Wednesday 6-3, 6-3.
In Auckland, Caroline Wozniacki began her warm-up for her Australian Open title defence with a comprehensive 6-3, 6-2 win over Laura Siegemund in the first round of the WTA Auckland Classic.
Wozniacki will play Canadian qualifier Bianca Andreescu in the second round while Williams plays fellow American Lauren Davis.
Canadian Eugenie Bouchard's comeback was almost derailed in an error-filled encounter with the 30-year-old Dutch journeywoman Bibiane Schoofs. Bouchard, the 2014 Wimbledon finalist, dropped her serve seven times but still managed to beat Schoofs 6-7 (5/7), 6-4, 6-4 to set up a quarterfinal clash with defending champion Julia Goerges.
Goerges, who did not get on court until after 10:00 pm, raced through her match against fellow German Mona Barthel 6-4, 6-4.
Tournament seventh seed Kirsten Flipkens was stopped in the second round by Spain's 22-year-old Sara Sorribes Tormo, losing 6-4, 1-6, 6-1 with Sorribes Tormo moving on to play Hsieh Sui-Wei in the quarterfinals.