Second seed Caroline Wozniacki fought back from two match points down to beat world number 119 Jana Fett in the Australian Open second round.
The Dane, 27, won 3-6 6-2 7-5 in two hours and 31 minutes, having been 5-1 down in the final set.
After saving the match points on Fett's serve, Wozniacki won six successive games to seal a place in the last 32.
"I am relieved to be through. I fought for every point and didn't give up, and it was rewarded," she told Eurosport.
"I am extremely happy to be through and to have another opportunity to be out here - it was definitely a crazy match today. It was experience that did it."
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- Switzerland's Belinda Bencic, who beat 2017 finalist Venus Williams in round one, was knocked out by Thai qualifier Luksika Kumkhum.
The 24-year-old world number 125 won 6-1 6-3 in one and hour 18 minutes to reach the third round of a Grand Slam for the first time.
French Open champion Jelena Ostapenko defeated Ying-Ying Duan in three sets, 6-3 3-6 6-4.