Simona Halep survived an epic encounter with unseeded American Lauren Davis to reach the fourth round of this year’s Australian Open.

The world number one came from a set down to take the 142-minute deciding set 4-6 6-4 15-13.  The match lasted three hours and 45 minutes in all.

Simona first had the chance to serve for the match at 8-7 in the decider and later had to recover from 0-40 on her own serve against the world number 76.

Victory sets up a tie with Japanese player Naomi Osaka in the fourth round after she upset 18th seed Ashley Barty in straight sets in her third round match.

Both players showed notable signs of injuries late in the third set.  Simona, who appeared to twist her ankle in the opening round, was limping and holding her upper leg at times towards the end.

Lauren Davis herself was treated twice for a toenail injury in the third set.