#3 Sloane Stephens
There is no writing off the 25-year-old Sloane Stephens. It is 2018 and the firebrand player is making her debut performance in the WTA Finals this time. The US Open 2017 champion and current World Number 6 has improved her game and her strategy manifold before coming into the Finals.
Stephens became the the first person to hand Naomi Osaka her first major blow in her debut WTA Finals match when she served her a 5-7, 6-4, 1-6 loss that left her at her wit's end. The next challenge was posed by Kiki Bertens, another strong contender from the Red Group, but Stephens unleashed her best ammunition to seal victory in a tight 7-6, 2-6, 6-3 scoreline, with the match having lasted 2 hours 20 minutes. By defeating Bertens, Stephens ended the Dutchwoman's nine-match winning streak coming into the WTA Finals.
Posed with the challenge of defeating top seed Angelique Kerber to gain entry into the semis, it can be anybody's day in the clash, with the odds slightly in favour of the debutant American.