Kiki Bertens bounced back from a sluggish start to defeat Donna Vekic in a thrilling final and win the St Petersburg Ladies Trophy on Sunday.

Second seed Bertens was 5-2 down in the opening set but showed tremendous spirit to battle back and complete a 7-6 (7-2) 6-4 victory for her eighth WTA title.

Vekic came out on top in a 20-shot rally in the opening game and went on to seal a break, but she was unable to see out the first set.

World number eight Bertens sprinted across court for a brilliant winner and a break to love in game eight and she went on to force an unlikely tie-break, which she claimed when Vekic failed to return a powerful serve.

The Dutchwoman forced Vekic from corner to corner with sensational groundstrokes before attacking the net and producing a sweet drop-volley to put herself into position to serve out the set.

Bertens' celebrations were cut short when Hawkeye showed Vekic had found the line and not gone long on championship point, but, after losing the next two points, she finally triumphed on a netcord winner.