Sabalenka was bidding for a first success at the season-ending WTA Finals, having made the knockout stages in each of the past four years and lost to Rybakina in last year’s showpiece.
But this was another occasion when Sabalenka, unlike Svitolina, appeared unable to maintain a positive outlook in testing moments.
After unravelling against Andreeva, she produced the positive start she desired by firing in an angled forehand winner to clinch an immediate break of serve.
But it was not long before Sabalenka’s game again threatened to fall apart as she conceded the first set by losing six of seven games – including twice being broken to love.
The response was excellent, a reduction in unforced errors helping her to a double break and a 5-1 lead before she served out the set at the second attempt.
However, the inconsistency returned and, with it, the frustration. After giving up an early lead in the decider, Sabalenka threw her racquet to the ground as Svitolina remained solid to swiftly turn the set around.
Sabalenka saved two break points, but set Svitolina up to take a third with a double fault, and the world number six kept her cool to serve out victory.