Hard work and peak fitness are the major concerns for world number two Caroline Wozniacki as she starts her first run to the US Open as a Grand Slam champion.
The 28-year-old Dane captured her first major title in January at the Australian Open, downing current world number one Simona Halep in the final, and the 2009 and 2014 US Open runner-up approaches the hardcourt campaign ahead of New York with new confidence.
Wozniacki, who captured her 29th career WTA title a month ago at Eastbourne, made a fourth-round exit at the French Open and lost in the second round at Wimbledon.
