Shaky-serving Serena survives second round test

Sep 2, 2015; New York, NY, USA; Serena Williams of the United States reacts after winning the first set against Kiki Bertens of the Netherlands (not pictured) on day three of the 2015 U.S. Open tennis tournament at USTA Billie Jean King National Tennis Center. Geoff Burke-USA TODAY Sports

NEW YORK (Reuters) - Serena Williams took her second step in a drive to complete the calendar-year Grand Slam but a lacklustre performance from the service line sent her straight to the practice court on Wednesday.

Williams, who would be the first woman in 27 years to win all four slam singles titles in the same year, beat Kiki Bertens of the Netherlands 7-6(5) 6-3 despite 10 double faults, including eight in the opening set of their second-round match.