Wimbledon champion Elena Rybakina came from a set down against Laura Siegemund to secure her place in the second round of the Slovenia Open.
Siegemund won the first set on a tie break, but Kazakhstan representative Rybakina stormed back to win the second before winning a tense 10-8 tie break in the crucial third set, surviving a match point in the process.
The world number 25's victory sets up a second round meeting with Tereza Martincova, who overcame a poor first set to beat Harriet Dart 0-6 6-4 6-1.
At the Chennai Open, top seed Alison Riske-Amritraj was beaten in straight sets in an upset defeat to world number 147 Anastasia Gasanova.
There were no such upsets for the second and third seeds though, as Varvara Gracheva and Magda Linette both cruised to victory to clinch their safe passage to the second round.
Elsewhere, Katie Swan beat Arianne Hartono 6-1 6-2 while India's number one singles player Ankita Raina was knocked out of her home tournament by Tatjana Maria.