After struggling to find her rhythm early on against the big-hitting lefty, Swiatek crushed an overhead to set up a break point, which she converted on her opponent's backhand error to cut the deficit to 5-3 and seize the momentum.

Vondrousova served for the set a second time at 5-4 but Swiatek broke again with a precise backhand winner up the line for 5-5 as she began to take control of the match, constructing points from the baseline and cutting down on her errors.

Swiatek completed the first set comeback on a double fault and a disillusioned Vondrousova went quietly in the second set.

Although she defended her title at the French Open for her fourth Grand Slam title, 2023 has been something of a disappointment for Swiatek, who did not get past the quarters of any of the other majors and lost her world number one ranking.

She came into her third WTA Finals with a ton of momentum, however, after winning her first WTA 1000 title of the season in Beijing, and has a chance to retake the top spot from Aryna Sabalenka in Cancun.

Vondrousova, who made her top-10 debut after emerging as the surprise winner of Wimbledon, is making her first appearance at the season-ending Finals, which features the top eight singles players and doubles teams in the world.

In the other Group B match-up of the evening, American US Open champion Coco Gauff needed just 56 minutes to defeat Ons Jabeur 6-0 6-1 in a rain-delayed clash, making for the fourth straight-set result in the singles tournament so far.

Gauff, who is seeded third in the tournament, will face Swiatek in her next match on Wednesday.