Simona Halep wasn't sure she would be healthy enough to defend her title at the hardcourt Dubai Tennis Championships, which start Monday, so didn't enter the event at first.
Feeling better, the Romanian postponed nose surgery to repair a deviated septum and got a wildcard.
"I know it's going to be tough to defend my title, but I'm trying to be healthy," Halep said Sunday.
Halep was upset in the Australian Open first round and went 1-1 last week in the Fed Cup quarterfinals against the Czech Republic, losing to Karolina Pliskova but defeating Petra Kvitova.
Halep has a first-round bye in Dubai but then faces either former No. 1 Ana Ivanovic of Serbia or Daria Gavrilova of Australia.
Halep jumped into the top-seeded spot when top-ranked Serena Williams withdrew Saturday citing illness, and the woman who beat Williams in the Australian Open final, Angelique Kerber, also pulled out with a thigh injury.
The third-ranked Halep isn't taking anything for granted, saying "every tournament is tough at this level and everyone can win it."
The fourth-seeded Kvitova, a two-time Wimbledon champion, arrived in Dubai as a solo act.
The Czech fired David Kotyza, her coach of seven years, after being upset by Gavrilova in the Australian Open second round last month.
"Now I don't have any coach and I'm by myself," Kvitova said, smiling. "I'm kind of enjoying this. I just feel more free than I felt before."