SINGAPORE - World No. 4 Simona Halep kicked off her BNP Paribas WTA Finals Singapore presented by SC Global campaign with a 6-2, 6-4 win over sixth-ranked Madison Keys at the Singapore Indoor Stadium on Sunday (Oct 23).

Debutante Keys opened the first round-robin match of the competition with an ace, hitting two easy winners to take the first game.

But Halep, who is here for the third consecutive year, reeled off five straight games to go up 5-1.

Serving for the set at 5-2, the Romanian held serve easily, winning the set after American Keys netted a forehand.

Both players exchanged breaks in the second set to tie the score at 4-4.

But Halep, the 2014 finalist, pulled away with a backhand passing winner to go 5-4 up and serve for the match.

Despite making two unforced errors on match point, she eventually won the match with a service winner.