BRISBANE, Australia — Serena Williams retired during the second set of her Hopman Cup match in Perth on Tuesday, completing a day of injuries and upsets for the leading players on the women's tour less than two weeks from the Australian Open.
Williams, who missed the U.S. team's opening loss to Ukraine on Monday because of inflammation in her left knee, was trailing 7-5, 2-1 against Jarmila Wolfe when she left the court in her first match of the season. Lleyton Hewitt beat Jack Sock 7-5, 6-4 and Australia Gold got a walkover in the doubles to win 3-0.