World No. 4 Kiki Bertens suffered a shock defeat in the Libema Open final on Sunday, as she failed to convert five championship points and was defeated 0-6, 7-6 (3), 7-5 by unseeded American Alison Riske.
The 27-year-old was totally untroubled on the grass in the first set as she broke Riske three times on her way to claiming the opener, but the second set was more closely contested.
Bertens broke Riske's serve and raced to a 4-1 lead, but the American was able to break back and level the set at 4-4, before saving five championship points to force a tiebreak.
Riske settled the set -- which had lasted one hour and six minutes -- with a 7-3 victory in the breaker.
The two women again exchanged breaks in the final set before rain caused a pause in play at 3-3.
The players were soon back on court and -- after a series of holds -- world No. 61 Riske broke serve to take the set 7-5 and win her second career title, five years after her first in China.