Maria Sharapova has acknowledged that only her willingness to fight until the last point earned her a dramatic victory over Russian compatriot Alexandra Panova.

The second seed saved two match points against the world number 150 before prevailing 7-5 in a deciding set, but despite her win, the 2008 champion has admitted that she struggled for answers against an inspired performance from her opponent.

The 27-year-old told Eurosport: "Fight was the only thing that I had today. I made so many unforced errors and my first-serve percentage was really low, and she was serving really well and moving me around the court.

"I didn't have many answers apart from that I fought to the end and managed to win the last point."

Sharapova will play either 31st seed Zarina Diyas or Anna Schmiedlova in the last 32.