Johanna Konta tumbled out of the Brisbane International with a straight-sets defeat in the second round.
Konta had made a perfect start to the new year after disposing of third-seeded American Sloane Stephens on Tuesday, but she was unable to repeat the feat as she suffered a 6-2 7-6 (7-2) loss to Ajla Tomljanovic, an opponent ranked nine places below her at 46.
British compatriot Harriet Dart lasted less than an hour as she went down 6-2 6-0 to Latvian Anastasija Sevastova.
The defeats, along with Andy Murray's loss, ended British interest in the hard-court tournament that serves as a warm-up for the Australian Open.
At the same event, world No 7 and fourth seed Petra Kvitova suffered a 7-5 7-6 (7-1) defeat to Estonia's Anett Kontaveit.
The upset of the day in Brisbane was supplied by Aliaksandra Sasnovich, who dispatched world No 4 and defending champion Elina Svitolina 6-4 0-6 6-3 to reach the quarter-finals.
At the ASB Classic in Auckland, top-seeded 2017 WTA Tour finals winner Caroline Wozniacki beat Laura Siegemund of Germany 6-3 6-2 and No 3 seed Su-Wei Hsieh saw off Monica Puig 6-1 7-6 (7-3).
Cramp came to Maria Sharapova's rescue as her Chinese opponent Wang Xinyu was forced to retire from their second-round match at the Shenzhen Open.
Wang, the youngest player in the tournament at 17-years-old, led 6-7 (4-7) 5-2 when she was forced to pull out and she sat on her chair receiving medical attention with a bandage on her left thigh.
Sharapova comforted the wildcard at the side of the court, saying "you played unbelievable OK? Unbelievable. You take care of yourself. If you play like that you'll be number one. I promise".
The five-time Grand Slam winner now faces world No 14 Aryna Sabalenka in the last eight.
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