Former world number one Roger Federer has admitted that he will have to play to the best of his ability to defeat Nikolay Davydenko at the Australian Open.

The two players will meet on Thursday for the right to advance through to round three in Melbourne.

Despite conceding that veteran Russian Davydenko is not the force that he once was, second seed Federer believes that he could easily be knocked out if he takes his opponent lightly.

"Obviously Nikolay, I know him [well]," said Federer. "He's my age. He played, I don't know, maybe 15 times. I played him at a time when he wasn't also in his best streak and in his best years, really, and he was in the top four or top five for a long time.

"It was two years ago I think he really struggled with his serve, but seems like he's coming back around. I had a very close match with him in Rotterdam last year.

"I should have won in two; ended up being 4-4, 0-40 in the third. I was very close to losing. Next thing you know, nobody talks about it. I went on to win the tournament and nobody talks about Nikolay.

"So it's nice to see him playing well again. And if I do play well against him, you're aware that he is a top player who can do a lot of damage. I better be well prepared and play well."

Davydenko was once ranked third in the world.