Second seed Maria Sharapova plays 31st seed Zarina Diyas at 08:00 GMT for a place in the last 16. That match will be followed by third seed Rafael Nadal v unseeded Dudi Sela. And I'm pleased to say we will have live text commentary on both those matches coming up shortly. That's it from me, though, so until next time, it's good morning from me. See ya!

Well, no one saw a Roger Federer defeat coming did they? The Swiss, who last won the Australian Open 2010, must wait another year. His last Grand Slam title came back in 2012. Will there be more drama later on today when Maria Sharapova and Rafael Nadal are in action in the evening session?

Rich:, external Felt all along that Seppi would eventually choke, but he held his nerve admirably. Got to think Federer is now in decline.

Image source, AP

"I just tried to enjoy playing on centre court again," said Seppi after his shock win over Federer. "It's not often you get the chance to play on centre court.

"I just tried to play my best and I did because I was playing Roger. You never feel comfortable playing against Roger, but I was focussing on my service game, I didn't have many chances on his serve."

Earlier in the day, 10th seed Grigor Dimitrov outlasted former finalist Marcos Baghdatis over five sets to set up a last 16 match against Andy Murray at the Australian Open.

Here's the developing report on Roger Federer's shock defeat in the Australia Open third round. Andy Murray had a little wobble in the final set, but was otherwise untroubled as he cruised past Joao Sousa.

Image source, Getty Images

Andreas Seppi's reward for victory over Roger Federer is a meeting with either Malek Jaziri or Nick Kyrgios in the last 16.

Roger Federer, a 17-time Grand Slam champion, has not lost this early at the Australian Open since 2000, the second year he played here. It is also the unseeded Seppi's first win against Federer in 11 attempts.

Seppi conjures up a beautiful forehand winner to bring up match point. Is it all over for another year for Federer? Yes it is! Seppi pulls out a forehand from the very top drawer, while on the stretch I should add, to pass Federer at the net and secure an unlikely victory. As ever, Federer is gracious in defeat.

Oh the tension! Federer secures a mini-break with a backhand winner, but then throws it away with a backhand error in the next. At 5-5, the Swiss is now just two points from defeat.

We're straight over to the Rod Laver Arena where Roger Federer is on the verge of getting dumped out of this year's Australian Open. The Swiss lost the first two sets to Andreas Seppi but hit back to win the third. We're in a fourth set tie-break, with the pair locked at 4-4.

Murray will play Grigor Dimitrov in the last 16, the Scot aiming to amend for last summer's Wimbledon defeat by the Bulgarian when they meet on Sunday. The Bulgarian 10th seed needed five sets to get past Marcos Baghdatis earlier today.

"I was up two sets and 4-1, but he got back into it," says Murray. "He competed very well. He always does and made it difficult in the end, but it was a good match.

"I'm feeling pretty good so far. I have played three quite quick matches which helps, but you expect the matches to get a little tougher as you go through each round so if you can conserve energy, that's always good."

Better from Murray in the first point, the Scot's aggressive play earning him the first point. But he hits too short in the next and Sousa whips the ball away for a winner.

The pendulum swings the other way as Murray somehow guides the ball back into court, when stretching on the run for 15-30, but Sousa responds well to level again.

Murray brings up match point. Sousa hits long, but is it long? Sousa wants to challenge, the Portuguese arguing with the umpire. But he eventually concedes and offers his hand to Murray. Victory, then, for the world number six but boy did he make it hard for himself in that final set.

Much better game from Murray, who flies through his service game to love in under a minute. That'll ease the frustration and quickly heaps the pressure onto Sousa, who will once again serve to stay in the match.

With a shadow now looming over most of the court, Murray chooses to ditch his baseball cap. The wardrobe tweak seems to help as he soon finds himself with two match points. Sousa saves the first with a forehand volley winner and is then relieved to see Murray dump a forehand in the net. Deuce.

Murray's frustration is clear, the Scot muttering to himself between points as he tightens up. A forehand sails long to gift Sousa game point. But back comes Murray, putting Sousa on the run and nailing a good passing shot which the Portuguese can't keep in play. Deuce.

Sousa punches the air and gives a glare up to his box as he wins the next two points to seal the game. On we go...

Roger Federer is serving to stay in the tournament over on the Rod Laver Arena.

The four-time champion is 5-4 down in the fourth set against Italian Andreas Seppi, who leads by two sets to one.

Better from Murray, who finds his range again and motors to a 40-0 lead. But it's clear that the Scot is getting a bit tentative and Sousa takes advantage, winning the next two points. Danger averted in the next, as Murray fires a backhand down the line to move 5-4 clear and Sousa will now serve to stay in the match.

Sousa has found something from somewhere and it's Murray who is now doing all the scrambling. And out of nowhere, we're level in the third set as Sousa holds to 15.

Murray looked to be cruising at 40-15, but he throws in a double fault and a tame forehand and suddenly we're at deuce. Sousa takes advantage of Murray's dip in form, bringing up only his second break point of the match with some aggressive play. And would you believe it? Sousa breaks as Murray frames a forehand! The Scot throws his racquet down in frustration. We're back on serve.