US Open semifinals

Published 0329 GMT (1129 HKT) September 9, 2016
Pliskova SerenaPliskova Serena
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In their lone previous meeting, Williams, right, beat Pliskova in California. Elsa/Getty Images North America/Getty Images
But saying she struggled with a knee injury, Williams wasn't at her finest. Al Bello/Getty Images North America/Getty Images
She made 31 unforced errors and hit six double faults to lose 6-2 7-6 (7-5). Alex Goodlett/Getty Images North America/Getty Images
Pliskova reached her first grand slam final. For her part, her game was working, including the big serve. DON EMMERT/AFP/AFP/Getty Images
Serena's loss meant Angelique Kerber wil rise to No. 1 in the rankings on Monday, ending Serena's long stay. JEWEL SAMAD/AFP/AFP/Getty Images
Kerber celebrated by beating Caroline Wozniacki 6-4 6-3 in the other semi. EDUARDO MUNOZ ALVAREZ/AFP/AFP/Getty Images