British number one Johanna Konta moved into the quarter-finals of the Brisbane International with a 4-6 6-1 6-4 win against wildcard Ajla Tomljanovic.
Konta, who ended a run of five straight defeats since August by beating Madison Keys in the previous round, won in two hours 26 minutes.
She will play Ana Konjuh or third seed Elina Svitolina in the last eight.
Wimbledon champion Garbine Muguruza withdrew for the fourth year in a row after suffering with cramp.
After losing a fluctuating opening set in which her serve was broken four times, fifth seed Konta raced 5-0 ahead in the next against 24-year-old Croat Tomljanovic, the world number 118.
Tomljanovic needed a medical time-out for treatment off the court and returned with heavy strapping on her right thigh but Konta soon wrapped up the set, in which her serve improved significantly and she offered no break point chances.
Konta continued to impress with the accuracy of her groundstrokes and served for the match at 5-2, but her Croat opponent struck some defiant blows and broke back, before holding serve with an ace.
Tomljanovic had three break point chances to level the match at 5-5 but Konta held on and sealed victory on her first match point.
"There wasn't a lot in it so I'm glad I stayed tough to come through that," the British player said. "It boosts the match fitness, every match is a battle."
World number two Muguruza was leading 2-1 in the deciding set of her second-round match against Serbia's Aleksandra Krunic in 30C heat.
But she collapsed following a serve and had to be helped from the court.
The 5-7 7-6 2-1 defeat ends any hope of replacing Romanian Simona Halep as number one before the Australian Open.
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"I cramp very few times," said Muguruza, adding that the problem started early in the second set.
"The last time I cramped up was actually at the Australian Open in Melbourne. Maybe it's the heat. Maybe it's the conditions. I don't know, but it's rare for me."
Muguruza's run of injury problems in Brisbane dates back to 2015 when she withdrew on the eve of the event with an ankle problem. A foot injury ended her 2016 campaign and a thigh problem led to her semi-final retirement last year.
The top seed had started well against unseeded Krunic, the world number 53, converting her seventh set point to win the first set before surging to a 5-2 lead in the second.
But Krunic took four of the next five games to force a tie-break, which she won 7-3 to send the contest into a deciding set.
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