Singapore - Simona Halep set her sights on breaking through for her first Grand Slam title on Sunday after securing the year-end world number one ranking -- and a vote of confidence from Roger Federer.
The Romanian became the 13th year-end women's number one despite struggling at the WTA Finals in Singapore, winning just once to bow out at the round-robin stage.
Halep was officially recognised with the end-of-year trophy and a sparkling new ring on Sunday.
Halep reached the top ranking for the first time earlier this month and narrowly held on when world number three Karolina Pliskova lost her semi-final in Singapore.
Her next challenge is a maiden Grand Slam win. Halep came desperately close in this year's French Open final, when she blew a set and 3-0 lead against 20-year-old Jelena Ostapenko.
"Of course, my new dream is to win a Grand Slam," she told reporters in Singapore. "I just want to work harder to get better, because I need to do that and we will see what is going to happen."
Halep admitted it would be a challenge to stay at world number one, a position which has been occupied by five different players this year. "I have to work harder to stay there," she said.
"I can imagine that it's going to be a little bit more difficult. Every tournament, every day is going to be a big challenge, starting now."
The 26-year-old recently received support from Swiss great Federer, who said Halep "deserves" to be world number one.
"I felt really proud of myself that Roger Federer could talk about me like that," Halep said. "It's a great feeling that I can finish the year number one."