Latest from wta finals
Garbine Muguruza now has a 13-2 record on Mexican soil, where she won back-to-back titles in Monterrey in 2018 and '19.
In a battle between two of the game's biggest hitters, Sakkari battled back from a break down and pounded three aces in the first set tiebreaker to take the early lead in the win-or-go-home group match.
Anett Kontaveit now has won 28 of her last 30 matches, including her title run at Ostrava. Prior to that strecth she had a 19-13 record for the year.