Roger Federer has been knocked out of the Australian Open as he suffered a shock third-round defeat to Andreas Seppi today.

Seppi made a great start as he stifled Federer early on, before he broke his serve and claimed the opening set.

The Italian continued to cause the 17-time Grand Slam champion problems with his aggressive approach, and in the second-set tie-break he unloaded a sequence of powerful ground strokes to help him take a two-set lead.

Federer went on the attack in the third set and he managed to force a break of serve, which was pivotal as he went on to win the set and prompt excitement in the crowd that a comeback was on.

However, Seppi didn't succumb to Federer's pressure and he held his nerve to clinch a fourth-set tie-break to win 6-4 7-6 4-6 7-6.

Seppi will now play either Nick Kyrgios or Malek Jaziri in the next round.