Angelique Kerber knows she faces a major challenge to win another grand slam title after her sensational Australian Open victory over Serena Williams.
Kerber pulled off a big upset to beat the world number one 6-4 3-6 6-4 on Rod Laver Arena on Saturday.
The 28-year-old German, who will rise to number two in the world rankings on Monday, had never reached a grand slam final before facing the legendary Williams.
And Kerber believes the talent of her rivals will make it difficult to repeat her success in Melbourne.
She said: "Against Serena, it's not so easy to win,
"I was feeling this as well. You must play really your best tennis to beat her. I played really good. I knew that I must go for it. I think it's still tough to beat Serena.
"But of course I think that a lot of new and good players are coming. They will challenge Serena. They will challenge me. They will challenge all the good players.
"Let's see what happens in the next few months or few years."
Kerber celebrated her maiden grand slam victory by taking a swim in the Yarra river on Sunday and also sprayed champagne as she posed with the trophy at Government House in Melbourne.