Iga Swiatek began her bid to regain the world number one ranking by recovering from a set and double break down to beat Barbora Krejcikova in her first match at the WTA Finals.
Swiatek, playing in her first competitive game since her US Open quarter-final exit, emerged a 4-6 7-5 6-2 victor against the Wimbledon champion in Riyadh.
The Pole is the third player in the last 30 years to achieve three or more seasons in a row with over 60 wins, after Martina Hingis (1997-2001) and Caroline Wozniacki (2009-2011).
Only Elina Svitolina (12) has played fewer matches at the WTA Finals than Swiatek (13) to achieve 10 wins at this event since the reintroduction of the Round Robin format in 2003.
But the Pole acknowledged the difficulties she faced against Krejcikova, saying she must improve if she is to retain her WTA Finals crown.
“Even though I played a lot of those [practice] matches,” Swiatek said afterward. “I kind of forgot for a while how it is to feel all those things, a bit different stress and emotions.
"For sure, I needed some time to adapt. The most important thing was that even though it happened, I managed to fight through that. And was patient enough to wait to get better.”
In Sunday's other match, Coco Gauff beat fellow American and doubles partner Jessica Pegula 6-3 6-2 in the second Orange Group match.
Gauff moved to a win-loss record of 51-16 in 2024, including the Olympics and team events, equalling her career-high from 2023 for WTA-level match wins in a calendar year.
She is now only the fifth player to claim 20 or more WTA top 10 wins before turning 21, along with Kim Clijsters (45), Maria Sharapova (39), Ana Ivanovic (26) and Wozniacki (23) since 2000.
"I think maybe I served better than previous times and this is our first time, I think, playing each other on indoor hard, so maybe that had something to do with it," Gauff said.
"I don't know. I think I know I've lost to her a lot, but it doesn't feel like it sometimes.
"Because we do practice a lot, and obviously, when we're playing sometimes I win practice sets, sometimes she does. So it doesn't feel like the head to head is as bad as it was."