Angelique Kerber loses to Karolina Pliskova in Cincinnati Open final
Angelique Kerber failed to end Serena Williams' 183-week run as world number one - losing to Karolina Pliskova in the Cincinnati Open final.
Germany's Kerber, 28, was beaten 6-3 6-1 by her 24-year-old Czech opponent, who gained her sixth WTA title.
American Williams, 34, has been world number one since February 2013, and is closing on Steffi Graf's record of 186 consecutive weeks at the top.
Williams withdrew from the tournament with a shoulder injury on Monday.
Kerber, who would be the first German to top the world rankings since Graf, said: "If someday it happens, it happens, but I will not be making too much pressure on this. I've had such a great year so far and it's not over yet."
It was Pliskova's first victory in a final against Kerber at the third attempt.
Kerber, the Australian Open champion, was broken five times in the match and only managed one of her own as she fell to her third defeat to Pliskova.