Germany’s Angelique Kerber poses with her birthday cake ahead of her Australian Open tie in Melbourne yesterday. Pic/Getty Images

Melbourne: World No. 1 Angelique Kerber gave herself the perfect birthday gift yesterday by reaching the Australian Open third round, but she had to work hard against fellow German Carina Witthoeft. The defending champ, who turned 29, battled through 6-2, 6-7 (3/7), 6-2 and will next face Czech Kristyna Pliskova.