The 27-year-old Romanian beat Sloane Stephens at Roland Garros to win her maiden Grand Slam title in June and will have spent 40 weeks at the top of the rankings by the end of the season, Reuters reported.
“Finishing the season as the world number one last year was a huge honor for me,” Halep said in a WTA news release.
“To do it for a second time in 2018 feels like a special achievement, especially having also won my first Grand Slam this year.
“It’s really tough to keep (the number one spot) because the pressure is every tournament... I feel like I’ve played a good level of tennis and I was consistent... consistent and strong, mentally and physically.”
Halep is scheduled to play in Moscow this week before rounding out her season at the WTA Finals in Singapore but suffered a herniated disc in her back this month, casting doubt on her participation in both events.
“I’m doing physio to try to make (my back) stronger, but I haven’t practiced 100 percent yet,” Halep added.
“If I can’t play here (in Moscow) I’m very doubtful that I will be able to play in Singapore... I don’t know now, but for sure I will take a decision for my health first.”