Naomi Osaka won the match on her fifth championship point[/caption] Japan’s Naomi Osaka beat Czech Petra Kvitova in a thrilling Australian Open final to win back-to-back Grand Slams and become the new world number one. The US Open winner, 21, missed three championship points in the second set but regrouped to win 7-6 (7-2) 5-7 6-4. The fourth seed broke for 2-1 in the decider, then served out to clinch victory in Melbourne. Eighth seed Kvitova, 28, was bidding for her first major title since being stabbed in a knife attack. Osaka was all smiles during the trophy presentation – in contrast to her US Open victory – and she continued a tradition of slightly awkward acceptance speeches. “Erm, hello. Sorry, public speaking isn’t my strong point so I hope I can get through this,” she said. “I read notes before this but I still forgot what I was meant to say. Thank you everyone, I am really honoured to have played in this final.” Two-time Wimbledon champion Kvitova, who said she was fortunate to be alive after the stabbing incident in December 2016, showed resilience to take the match into a third set as momentum swung from side to side. Victory seemed to be inevitable for Osaka before Kvitova broke back for 5-5 in the second, then going on to win 12 points in a row to lead for the first time since the start of that set. However, after shedding tears at the end of the second set while she left the court for a bathroom break, Osaka regained focus to take a decisive advantage in the decider. She went on to become the first player since American Jennifer Capriati in 2001 to follow her maiden Grand Slam win immediately with another triumph. She missed a fourth championship point with a long return, but took the fifth when Kvitova hit a forehand wide. A smiling Osaka dropped to her haunches on the baseline before returning to her chair and covering her face in shock as she savoured the moment. Osaka, who replaces Simona Halep at the top of the rankings after the Romanian’s 48-week stint, becomes the first Asian player to be world number one. She is also the youngest to hold top spot since Denmark’s Caroline Wozniacki, then aged 20, took the ranking in 2010.