The world number one Simona Halep was troubled by unseeded American Lauren Davis, but she managed to survive the epic battle to reach the Australian Open fourth round.
The Romanian had to save three match points in the decider before eventually winning 4-6, 6-4, 15-13 after three hours and 45 minutes. The final set lasted for incredible 142 minutes before Halep finally served out the match at the fourth attempt.
"I never played a third set so long. I'm almost dead," she said.
"My muscles are gone. I don't know how my ankle is because I can't feel it any more."
The contest equalled the women's singles Australian Open record for longest match in terms of games played, tying the 1996 quarter-final between Chanda Rubin Arantxa Sanchez Vicario, which Rubin won 6-4 2-6 16-14.