Sofia Kenin kisses the Daphne Akhurst Memorial Cup after winning against Garbine Muguruza in their women's singles final match in Melbourne on Saturday. AFP

Surprise package Sofia stuns Muguruza to win Australian Open title

The 21-year-old's father is her coach but the rest of the family was back in the United States as Sofia announced herself to the sporting world with her first Grand Slam title.

Former US tennis player Lindsay Davenport hands the Daphne Akhurst Memorial Cup to Sofia Kenin. AFP

The 14th seed showed all her trademark battling qualities to stun two-time Grand Slam champion Garbine Muguruza 4-6, 6-2, 6-2 in Melbourne.

"I called her right after the match just to tell her that everything's fine, I won, she can just relax now," a beaming Sofia Kenin told reporters, glass of champagne in hand, referring to mother Lena.

"She's been really stressed at home, very superstitious.

"I told her I'm not going to be able to talk to you for hours, but at least you know that I won.

"I'm coming home, you can give me the biggest hug of your life."

Sofia Kenin is greeted by her father Alex after defeating Garbine Muguruza. AP

At least Lena did not suffer alone and was accompanied by Sofia Kenin's grandmother, sister and the family dogs back in Florida.

"They don't watch, my mom cannot watch me," said Moscow-born Sofia Kenin, a proud American who will now usurp Serena Williams as the top-ranked player from the United States.

"She doesn't like watching, it's fine."

Sofia Kenin, who dumped top seed and home hope Ashleigh Barty out in the semi-finals, said repeatedly that her mental strength was key to the biggest title of her tennis life.

She also put her hand over her mouth on several occasions, almost disbelieving at what she had achieved, and later said she was "on cloud nine."

Sofia Kenin poses for a photograph with the ballgirls. AP

Sofia Kenin pinpointed the fifth game of the deciding set, when she was down 0-40 on her serve before reeling off five clean winners in a row to go up 3-2, as the moment the match swung in her favour.

"I can remember that game very well, that's the game I feel changed things," said Sofai, who was born in Moscow but moved with her family to the United States as a baby in search of a better life.

"I knew I needed to come up with the best shot, five best shots of my life."

"It got me to win a Grand Slam," she added, smiling broadly once more. "I had to play some of my best tennis. I did. After that, I was on fire.

"I was ready to take the beautiful trophy."

Agence France-Presse