SINGAPORE -- Naomi Osaka and Sloane Stephens, the past two U.S. Open champions, will make their career debuts at the WTA Finals by playing each other in their first match in Singapore on Monday.
The initial stage of the eight-player WTA Finals field is a round-robin competition with two teams of four players. The two players with the best record from each round-robin group advance to next Saturday's semifinals.
It has been a whirlwind six weeks for Osaka, a dual Japanese-American citizen who plays under the Japanese flag, since winning the U.S. Open.
Her Open victory -- the second title of her career with the first coming at Indian Wells in April -- was marred by controversy as opponent Serena Williams initiated a number of run-ins with umpire Carlos Ramos during the match.
"For me, I think I'm playing tournament after tournament, so I don't really have time to think about, like, my life changing or anything," said Osaka, of her new celebrity status. "So, yeah, I feel like I would need the year to end to maybe process more.
"I mean, with the recognition part, I do feel a bit different," she added. "Like before it was only Japan I felt like people know me. But now like even here, I guess this is Asia, too, though, so it doesn't really count, but like in the airports and stuff. I just think that that's kind of funny."
Stephens, 25, who won the U.S. Open in 2017, is looking forward to this second outing against Osaka. She won their first meeting in the 2016 Acapulco quarterfinals in straight sets.
"I think it will be super fun and it's a great matchup," Stephens said. "Obviously everyone works all year long to get here. It's my debut here as well as hers, so it's new territory for both of us. We both have had amazing accomplishments so we'll be looking forward to the match and we'll see what happens."
Both are hoping they handle this new experience of qualifying for the year-end tournament with ease.
For Stephens, the biggest concern is adjusting to the unfamiliar round-robin format.
"I haven't played a round-robin since I started playing tennis at Sierra Sport and Racquet Club, and you had to play the round robin to advance in your ladder," Stephens said. "Yeah, I was, like, 10. So I'm really not sure how it works. But I think you just play and try to win and whatever happens, happens."
Osaka is hoping that just being part of the WTA Finals won't give her the jitters.
"I hope I don't get overwhelmed," Osaka said. "You never really know how you're gonna feel until you're in that moment. So I can only hope that I'll play well and I won't get, like, nervous or anything, which I'm sure I will, but I feel like that's all part of the process."
The two join Angelique Kerber, the reigning Wimbledon champion, and Kiki Bertens, who qualified for the tournament when No. 1 Simona Halep withdrew because of a herniated disc in her back, in the Red Group. Kerber and Bertens play Monday's second scheduled match.
The competition gets under way with White Group matches Sunday.
Petra Kvitova, the 2011 WTA Finals champion, will play Elina Svitolina, who debuted here last year, in the opening match. Caroline Wozniacki, the defending champion, faces Karolina Pliskova, making a third consecutive appearance here, in the second match.
Despite not being able to play here, Halep is in Singapore and received the WTA Player of the Year award at the black-tie WTA Finals Gala on Friday night. The Romanian won her first Grand Slam title at this year's French Open and was an Australian Open finalist.
"Winning a Grand Slam and finishing No. 1, I think it's the most that I could ask for," Halep said. "I had also tough moments, because Melbourne, it was really tough to get over and to come back stronger.
"I'm proud that I could come back stronger and I could make a better result. So I think definitely, actually, is the best year of my career."