3 Min Read MELBOURNE (Reuters) - Serena Williams put on a vintage display of power tennis to ease into the second round of the Australian Open with a 6-1 6-1 drubbing of Germany’s Laura Siegemund on Monday before rushing off court to catch the end of the Super Bowl. First-round matches at Grand Slams have rarely presented a problem for the 39-year-old American, who has lost just one of 77 over her long career at the majors. Williams admitted to some concern that a shoulder injury which forced her to withdraw from her warm-up tournament last week would hinder her serve, and that perhaps expl...