Prior to the start of the WTA Finals on Saturday, 25-year-old Rybakina had not played on tour for two months because of a combination of illness and injury, and her opening match against Paolini ended in a straight-set defeat.

The former Wimbledon champion had looked fatigued during that match but started stronger against Zheng, putting pressure on the serve early on with the Chinese seventh seed forced to save two break points early in the opening set.

Momentum then swung Zheng's way as she sealed a first break of serve on the way to a 4-1 lead, but as her unforced error count started to creep upwards, Rybakina was able to fight back into the set by winning three successive games.

Yet in the deciding tie-break, Rybakina nudged a return long to wrap up the opener for Zheng on her second set point.

Little could separate the pair at the start of the second set, but Rybakina found a much-needed higher gear after going 3-2 and a break down.

After getting the immediate break back, she saved two further break points from 15-40 down, reeling off three aces in the game before landing a backhand on the Zheng baseline.

That was in the second of four successive game wins to seal the second set, but Rybakina came unstuck again in the decider.

As she grew weary, opponent Zheng was able to capitalise with a break for 3-1 from which she never looked back, wrapping up her maiden WTA Finals win on her first match point.