Murray beats Robert 6-1 6-2 6-7 (6-8) 6-2
Briton to face Federer in last eight
Federer sees off Tsonga 6-3 7-5 6-4
Nadal overcomes Nishikori 7-6 7-5 7-6
* denotes next to serve
Rafael Nadal has broken back in the second set against Kei Nishikori to level at 4-4, but the Spaniard took a tumble in the following game and broke his shoelace in the process. Nadal asks the umpire whether he can change his footwear and sprints off the court to the nearest sports shop.
Murray may have the break but Robert is posing a threat. He is keen to get to the net, and does so at 15-15 to good effect, producing an inch-perfect volley to move ahead in the game. That, though, is followed by a sloppy drop shot which doesn't quite creep over the net.
But Murray fails to punish him, putting a forehand into the net to give Robert a break point. It goes begging, though, as Robert overhits a backhand, and Murray holds.
Miles Maclagan
Former coach to Andy Murray and Laura Robson on BBC Radio 5 live sports extra
"Robert's been around a long time. He knows he can't just play a solid match. He's going to have to take some chances just to keep Murray on his toes. He knows if he allows Murray to get comfortable he won't be around for long. For Andy, all the pressure is on him. It's a lost opportunity if he doesn't win it."
Robert shows some nice early signs of form in this game, including a deadly smash from the back of the court after conceding the first point, but Murray steps up a gear at 30-30 to force a break point and Robert fires long. Advantage Murray.
After a testing first service game in which he faced break point, Murray holds with ease this time. Robert fails to get a couple of the Scot's serves back as Murray moves to 40-0, then finishes off with an ace.
It may be the biggest game of his life, but is Robert nervous? Not a chance. He holds his serve with ease, the highlight a stunning forehand which leaves Murray rooted to his spot at the back of the court.
Image source, APRafael Nadal isn't having everything is own way over on Rod Laver Arena. The top seed, who won the first set in a tie-break, has been broken by Kei Nishikori in the second set and the Japanese player leads 3-2.
A fine start by Robert. After a couple of Murray forehands earn him the opening two points of the match, the Frenchman capitalises on a weak volley as he works his way back to earn a break point. He shanks a forehand long though as the British number one resists it, before a driven backhand winner down the line ensures Murray holds.
Murray to serve first...
Piers Newbery
BBC Sport at Melbourne Park
"It's a bright and breezy day at Melbourne Park, around 21C for the start of play. Kim Sears was the first of Team Murray to take their seat, followed a few minutes later by Ivan Lendl, Dani Vallverdu and Jez Green trooping in, all wearing shorts and carrying towels over the shoulders. There were smiles all round, it looked like they were on an all-inclusive break and heading for the pool. Game-faces are now being arranged."
What else is happening? Catch up with our latest scores and results:
Robert trains at Patrick Mouratoglou's tennis academy. "He's just playing for pleasure and he doesn't feel any kind of pressure," Mouratoglou told BBC Radio 5 live sports extra. "It happens sometimes, when you're in the last year of your career you play with no pressure. He got a good draw and took advantage of everything. It's good to have luck, but you have to take advantage of everything."
That experience is about to begin. The players are nearly finished their warm-ups and we're almost ready to go on Hisense Arena.
Robert is relishing the prospect of going up against the world number four, with the prospect of a place in the quarter-finals at stake.
The 6ft 1in right-hander describes his style as "casino tennis, hitting crazy shots", and he has hit 100 winners in his opening three matches.
"I've played some top players - Rafael Nadal when he was very young, Andy Roddick, Gael Monfils, Tomas Berdych, and I'm always happy to play a new one," he said.
"It's going to be a good experience for sure."
Image source, Getty ImagesRobert is not the only player to have impressed this week, mind. Andy Murray, still finding his way back at the top level after a back injury, has made it this far without dropping a set, seeing off Go Soeda 6-1 6-1 6-3, qualifier Vincent Millot 6-2 6-2 7-5 and 26th seed Feliciano Lopez 7-6 (7-2) 6-4 6-2 in the opening three rounds.
He has never lost to a player ranked as low as or lower than Robert's 119 at a Grand Slam event and has a 9-1 record against "lucky losers" at Tour level - his only defeat coming against Jeremy Chardy at Cincinnati-1000 in 2012.
Image source, Getty ImagesTwenty four hours after Serena Williams' shock exit, another of the favourites for the women's title is out after third seed Maria Sharapova was beaten 3-6 6-4 6-1 by 20th seed Dominika Cibulkova earlier on Monday. Defending champion Victoria Azarenka did make it through, though.
BBC Radio 5 live sports extra
Our colleagues at Radio 5 live sports extra are now on air with live commentary from Hisense Arena. They will also have coverage of the intriguing match between Roger Federer and Jo-Wilfried Tsonga later on Rod Laver Arena.
Anybody expecting an upset today? Or will it be plain sailing for Murray? And has the British number one done enough so far to suggest he can win the title? Send us your thoughts to #bbctennis, external on Twitter or via 81111 on text and we'll use the best ones in this live text commentary.
Murray is playing Robert for the first time and the Scot is aware of the challenge posed by a player who has already won five matches at Melbourne Park.
"It's obviously a big achievement," said Murray. "I know him a little bit from when I was coming through the Futures and Challengers. Playing in Europe and in the UK, I've seen him play a little bit.
"He's 33 years old and it could be easy to stop playing if you're not in the top 100 or necessarily making a great living.
"But it does show if you stick at it and you're professional, when your chance comes, you take it and you can do great things. It's great for him and good for tennis as well."
Image source, Getty ImagesRobert defeated Aljaz Bedene, Michal Przysiezny and fellow "lucky loser" Martin Klizan in the opening three rounds, dropping only one set, and is now looking to become the lowest-ranked player to reach the Australian Open quarter-finals (since the ATP rankings were introduced in 1973).
At 33 years and 254 days, Robert is the oldest man to reach the round of 16 at the Australian Open since Andre Agassi made it to the quarter-finals aged 34 years and 276 days in 2005.