Simona Halep saved three match points and served for victory four times in an extraordinary encounter against Lauren Davis before eventually booking her spot in the fourth round of the Australian Open.The top seeds in the women’s tournament have all had their dramas this week, but none quite like this.American Davis traded toe-to-toe with the world number one for three hours and 44 minutes, but Halep finally forced a match point and took it for a 4-6, 6-4, 15-13 victory.The 26-year-old said: “Definitely it was a very tough match. So long. I never played the third set so long. I was very happy I could stay and win it. I’m almost dead but I’m happy we could show great tennis.”The final set lasted two hours and 22 minutes, while the 48 games equals the most for a women’s match in Australian Open history, tying the 1996 quarter-final between Chanda Rubin Arantxa Sanchez Vicario, which Rubin won 6-4, 2-6, 16-14.Halep suffered an ankle injury in round one, but looked to have shrugged it off in a convincing win over Eugenie Bouchard on Thursday.Her biggest problem here was Davis, ranked 76, but playing significantly above that, as she came from a break down to take the opening set in her first ever match against a world number one.Halep hit back to level and it appeared the danger might have passed, but Davis simply would not go away.Three times the top seed served for a place in the fourth round at 5-4, 6-5, and 8-7 and three times Davis broke back.At 5ft 6in for Halep and 5ft 2in for Davis, this was a clash between two of the smaller players on the women’s tour, but what they lack in height they more than make up for in speed and agility.The court coverage from both was exceptional, but it was Davis’ belief that really stood out, the American having no qualms about unleashing big shots at the most important moments.On and on they went, the cooler Melbourne temperatures making things easier, but this was still an immense physical effort from both women.After saving four break points at 10-10, Davis looked poised to clinch victory when she moved to 0-40 on the Halep serve in the next game only for the Romanian to fight back.The effort was taking its toll on Davis’ toenails and she took an emergency medical time-out before saving five more break points in the next game.After the match, she had this to say about her injury, and we warn you, it's rather gruesome."I think my second toes are infected. I was just jamming them a lot with how much I was moving around the court."That first match point just, I felt something and I couldn't really put any pressure - it was my right toe, and then it eventually was my left toe, also.

"The trainer wrapped them really well and I was able to move fine after that."

Asked if the toenail had come off, she smiled: "It's about to.

"It was very difficult. I had never really had that happen before. They have been sore but not like that. Like I said, I couldn't really put any pressure on them.

"It also took me by surprise because it came on so suddenly."