Simona Halep saved a match point before defeating Canadian teen Bianca Andreescu 3-6, 7-6, 6-3 at the WTA Finals in Shenzhen.
Both players sought medical treatment during the match, with Halep getting her foot treated while Andreescu had a lower back problem.
Elsewhere, defending champion Elina Svitolina stretched her unbeaten run at the season-ending tournament with a 7-6, 6-4 win over Karolina Pliskova.
Halep and Svitolina are now 1-0 in the Purple Group, while Andreescu and Pliskova are 0-1.
Kane double rescues England in comeback win over DR Congo
Captain Harry Kane came to England's rescue as they came from a goal down in a battling 2-1 win over the Democratic Republic of Congo on Wednesday to seal their place in the last 16 of the World Cup.
Gauff survives Wimbledon scare, Krejcikova rallies past Andreeva
Coco Gauff managed to shrug off her Wimbledon gremlins in the nick of time to avoid another early exit on Wednesday.
Sinner, Medvedev and Sabalenka reach Wimbledon round three
Defending Wimbledon champion Jannik Sinner had several members of Europe's Ryder Cup team watching his second-round clash with Nuno Borges on Wednesday and in golfing parlance he kept it straight down the middle in a relatively risk-free victory.
Osaka brings the style again to beat Gasanova in Wimbledon second round
Four-times Grand Slam champion Naomi Osaka continued her impressive start to her Wimbledon campaign with a clinical 6-3 6-2 victory over Russian qualifier Anastasia Gasanova to reach the third round on a sunny Wednesday.
First-half goals send Mexico to comfortable 2-0 victory over Ecuador
Julian Quinones delivered a goal and an assist in the first half for Mexico, who maintained complete control in front of their vocal home fans to earn a 2-0 World Cup victory over Ecuador in a round of 32 match on Tuesday at Mexico City.
