Japan’s Naomi Osaka said she was “in a state of shock†Saturday after holding her nerve to battle past Petra Kvitova to win the Australian Open in a three-set thriller that also delivered her the world number one ranking. The fourth seed and US Open champion triumphed 7-6 (7/2), 5-7, 6-4 in a 2hr 27min epic over the Czech eighth seed to claim back-to-back Grand Slams and become the first Asian, male or female, to hold the top spot.