The German lost a first set tiebreak but recovered to triumph 6-7, 6-2, 6-3 in the season-ending event which features the top eight ranked players available.

Kerber, this year’s winner at the Australian Open and US Open, was also a break down in the third but had enough to eventually get past the Slovakian.

"Domi is a tough opponent and I knew that I had to play my best tennis," said Kerber, the top seed.

"I was trying to stay positive in the third set, play my game, be aggressive and just go for it. 

"I was also really concentrating on getting my first serve in.

"It was a really close match."

Kerber replaced American Serena Williams - who is missing the tournament with a shoulder injury - as world number one last month.

In the second match in the red group, Romania’s Simona Halep, the third seed, roared past US player Madison Keys 6-2, 6-4.

She said: "I think I played exactly what I had to play against her.

"I was focused.

"Everything went as I wanted, so I'm happy."

Two players from each group will qualify for the semi-finals on the hard courts at the Singapore Indoor Stadium.

The white group will begin tomorrow with Poland’s defending champion Agnieszka Radwanska meeting Svetlana Kuznetsova of Russia.

In the other clash, the Czech Republic’s Karolína Pliskova will meet Spain’s Garbine Muguruza.