Simona Halep remains in the hunt for the Miami Open title after fighting back to see off Slovenian world number 93 Polona Hercog.
The world number three lost the opening set and needed a tie break in the second to level matters, before going on to claim a 5-7 7-6(7-1) 6-2 victory.
“She played unbelievable and it was such a tough match,” said Halep after her win.
“It was good to play for almost three hours though. I slowly found my rhythm but I always had belief so if I can keep doing this, I will have a good tournament.”
The Romanian star will take on veteran Venus Williams next after the American overcame 14th seed Daria Kasatkina in the third round.
Halep is 1.40 to beat Williams and 2.05 to win 2-0, while Williams can be backed at 2.80 to secure the victory.
The 27-year-old could move to the top of the rankings again if she goes all the way in the Premier Mandatory event.
Current world number one Naomi Osaka fell in the third round and Halep will top the rankings again if she wins the event, or reaches the final and loses to any player other than world number two Petra Kvitova.
Halep is the 3.60 favourite to win the title in Miami, Kvitova is 6.00 and French hopeful Caroline Garcia is priced at 29.00.