Late entry Kiki Bertens registered a shocking victory against World No. 1 Ashleigh Barty with a comeback three-set victory in the season-ending WTA Finals in Shenzhen Tuesday.

All four players can qualify in the Red Group after Belinda Bencic’s three-set victory over Petra Kvitova in the later match.

In the start, Bertens was in trouble with a set and a break down, but she bounced back with some aggressive play at the net to douse the fire in Barty, who could have sealed a spot in the semi-finals with victory.

The world No.10 won 3-6, 6-3, 6-4 in two hours and nine minutes in a see-saw match featuring 12 breaks of serve.

“Of course you’re always ready to play, but I did not see it coming today. In the beginning I was struggling. As the match continued, I felt better and better,” Bertens said.

Bertens was added as a late replacement for world No.3 Naomi Osaka, who earlier in the day withdrew from the round-robin tournament due to a shoulder injury.

The 27-year-old was slightly nervous and dropped her first three service games. Barty, who has locked up the year-end No.1 ranking, pounced to run away with the first set. However, then Bertens adopted an aggressive that left Barty’s serve broken five times through the second and third sets as Bertens stormed to her first victory over the Australian.

Barty lamented letting slip her early lead. “I wasn’t able to execute as cleanly when I was up in the score line,” she said.

Winless Kvitova plays Barty on Thursday and Bencic meets Bertens to determine the winners from Red Group.