This time the tears were of joy. Tennis already had a star in Naomi Osaka; now it has a superstar. Despite squandering three championship points at 5-3 in the second set, the Japanese regrouped brilliantly to beat Petra Kvitova 7-6 (2), 5-7, 6-4 to win a dramatic Australian Open final. Her second consecutive grand slam title ensures she will be the new world No 1 and aged 21, there is surely a lot more success to come.

Beaten Petra Kvitova believes she can win another grand slam Read more

Last September, Osaka was reduced to tears when the crowd booed after a controversial US Open final in which Serena Williams lost her cool. On Saturday, the tears flowed again at the end of a high quality, see-saw final, in which she lost her way and then found it again, her steely character coming through, just as it had in New York. As Kvitova’s final forehand return flew wide, Osaka fell to her haunches, her head in her hands.

“I still feel very shocked,” Osaka said. “[At the end] I felt like the match wasn’t completely done but it was done. It’s one of those moments where you are fighting so hard and then when it’s finally over, you’re still in the state of competition.”

Play Video 1:31 'I forgot to smile': Naomi Osaka reacts after her Australian Open triumph – video

Having received the trophy from Li Na, the first Asian woman to win a grand slam singles title when she triumphed at the French Open in 2011, Osaka said she had forgotten the notes she had written about what to say. “I forgot to smile,” she said later. “I was told to smile. I was panicking.”

She is the first woman to follow her first grand slam title by immediately winning the next one since Jennifer Capriati in 2001 and the first since Williams in 2015 to win two majors in a row.

This time last year, she was ranked No 72; now she owns two slam titles and is top of the pile as the No 1 on the planet for the first time.

This was a performance full of maturity, even more remarkable given her age and relative lack of experience. Before the final, much of the focus had been on Kvitova and the possibility she could crown a fairytale comeback with a third major title, just over two years after she was attacked with a knife in her own home, an incident that left her needing several hours of surgery to save her left hand.

Had Osaka not been in the final herself, the chances are that she would have been willing Kvitova to victory, so popular is the Czech with her fellow players and so incredible has been her comeback. But there is something special about Osaka, something that means that she is able to stay calm, even under the most intense pressure, and get the job done.

It was a great final, full of brave hitting, good serving and some outstanding rallies, not to mention the tension, with not only a slam title but the No 1 ranking on the line.

Play Video 2:37 'It's painful': Petra Kvitova reflects on Australian Open loss to Naomi Osaka – video

At 6-7, 3-5, 0-40 on the Kvitova serve, it looked done and dusted, the consistency of Osaka having been key as she pulled away. But with the finishing line in front of her, the Japanese blinked.

Kvitova, the champion at Wimbledon in 2011 and 2014, sensed her chance, holding serve with some bold hitting, breaking in the next game, saving a break point to go ahead 6-5 and then breaking again as Osaka threatened to self-destruct. It was then that she took a bathroom break, shedding a few tears as she willed herself to bounce back. “I told myself I had no right to feel entitled, that she was a great player. I didn’t have a right to expect myself to win. In the third set, I shut down my feelings.”

When Kvitova held serve to love at the start of the decider, a turnaround looked possible, even likely. But a brilliant backhand on the second point of her serve at 0-1 settled Osaka down and from then on, the momentum changed.

Naomi Osaka v Petra Kvitova: Australian Open women's final – live! Read more

Osaka won three consecutive games to lead 3-1 but even then it was not done. Kvitova had a chance to break back for 3-3 but Osaka saved it. When Kvitova held from 0-40 down at 4-2, Osaka might have been having flashbacks but she held firm to serve out for victory.

Kvitova, too, was fighting back the tears. “It’s crazy, I can hardly believe I just played a final of a grand slam again,” she told the crowd. “It was a great final. Well done Naomi. For me it’s a big honour to have this [runners-up] trophy. Thank you to my team. You stuck with me when we didn’t know if I would even be able to hold a racket again.”

Osaka said she had dreamed of being No 1 but that her achievements were still surprising. “It still hasn’t sunk in yet.”