Roger Federer has said that he knew his third-round match against Andreas Seppi was not going to be "very simple" at the Australian Open.

The second seed became the highest-ranked player to exit in the men's draw so far when he lost in four sets to the Italian.

The 17-time Grand Slam champion told reporters: "I felt for some reason yesterday and this morning it was not going to be very simple today. Even in practice I still felt the same way.

"I was just hoping it was one of those feelings you sometimes have and it's totally not true and you just come out and you play a routine match. I feel like that very often and then, you know, I come out and play a good match.

"Sometimes you feel too good and then you play a horrible match. But I was aware that this could be a tough match and I wasn't mistaken this time around."

The exit is Federer's earliest in Melbourne since 2001.