World number one Serena Williams powered past Angelique Kerber in her opening match at the WTA Championship in Istanbul.
American Williams saw off her German opponent 6-3, 6-1 on her way to clinching victory on Tuesday.
Already guaranteed the WTA rankings number one spot, Serena is on a quest to finish the season on a high by becoming the first player to successfully defend the season-ending title since Justine Henin in 2007 and win a fourth crown overall.
She broke the ninth seed German’s serve at the first opportunity, amassing 31 winners, but also mixing her game to win the point on each of the 14 occasions that she ventured to the net.
“I feel really good. She’s beaten me before so I was a little nervous and really focused,” said Williams.
“It’s such a tough tournament. Every match you have to be focused. I’m happy, but I have to get focused again.”
Elsewhere, Victoria Azarenka fought hard to secure a 7-6 (7-4), 6-2 victory over world number seven Sarah Errani.
The Belarussian was 5-2 down to Italy’s Errani in the first set before struggling to take it on a tie break in an hour and 28 minutes.
Errani took time off for a treatment on a calf injury in the second set, which allowed the two-time Australian Open champion to take absolute control of the game, winning the final four games to complete victory.
Poland’s Agnieszka Radwanska, seeded third, lost 6-4, 6-4 to the Czech Republic’s fifth seed Petra Kvitova.