Angelique Kerber was forced to dig deep in her WTA Finals opener before the German world number one battled past Dominika Cibulkova 7-6(5) 2-6 6-3 in a high-class baseline slugfest at the Singapore Indoor Stadium on Sunday.
Earlier, Simona Halep got her campaign off to a perfect start when the Romanian world number four dominated an erratic Madison Keys to kick off round-robin play in the elite eight-woman, season-ending event with a 6-2 6-4 victory.
First-time finalist Cibulkova opened with a double fault and Kerber, who won two grand slam titles in 2016, took advantage of her opponent’s nervy start to grab an immediate break without having to do much more than get the ball over the net.
By contrast, the German found her rhythm right away as she located the corners with ease and used her brilliant retrieving skills to make Cibulkova always play an extra shot when it appeared the point had already been won.
The Slovakian, who won her third title of the year in Linz earlier this month, slowly worked her way back into the set with her high-intensity game and pressured Kerber enough to make her cough up two double faults to tie things up at 4-4.
The pair were now slugging it out on the baseline and after both held serve through to a tiebreaker, Kerber kept her nerve in the face of some tremendous pressure to edge ahead in the thrilling encounter.
Undeterred, Cibulkova made a fast start to the second set as Kerber wavered, breaking her opponent twice in a row to race into a 4-0 lead and, while the German threatened to mount a comeback, the seventh seed drew level with a forehand winner.