World number one Aryna Sabalenka's wait for a singles title on grass goes on after losing in the Berlin last four to Jessica Pegula on Saturday.
Her US rival won 6-4, 6-7 (4-7) 6-0 as Sabalenka's struggles on the surface ahead of Wimbledon starting a week on Monday were again laid bare.
A two-hour break due to rain in the middle of the second set tie-break, with Pegula leading 3-1, seemed to give the Belarusian the chance to gather herself after a mixed first set.
The four-time Grand Slam singles champion hit back to win the second set tie-break but was then blown away by the third seed in the decider.
Czech Linda Nosková faces Filipino Alexandra Eala in the other semi-final at the Steffi Graf Stadium in the German capital.
