WHAT looked a routine win for Andy Murray turned into a bit of a struggle before he finally saw off French lucky loser Stephane Robert to reach the quarter-finals of the Australian Open.
Murray missed four match points in the second set but ensured there was no miracle comeback for Robert by wrapping up a 6-1 6-2 6-7 (6/8) 6-2 victory on his sixth chance.
A much greater test awaits against Roger Federer in the last eight after he saw off Frenchman Jo-Wilfried Tsonga 6-3 7-5 6-4.
Murray said of Robert: "He's a fun player to watch but not fun to play. He plays all the shots, he's very unorthodox. He made it very tough for me.
"If you can, you want to close matches out when you have the opportunity. I had chances on my serve, I didn't get them. I tried to stay focused at the beginning of the fourth, got an early break and that helped."
For two sets it was virtually a stroll in the park for the Wimbledon champion.
Of all the possible opponents he could have faced in the fourth round, Robert was among the most unlikely.
The 119th-ranked Frenchman initially lost in the final round of qualifying but secured a lucky loser spot 10 minutes before meeting Aljaz Bedene after Philipp Kohlschreiber pulled out.
Robert won that one and two more to become the first lucky loser ever to reach the fourth round at Melbourne Park. It took two hours and 21 minutes but Murray was finally through to his 12th grand slam quarter-final in a row at tournaments he has contested.
Robert stayed on court to soak up some deserved applause as a relieved Murray celebrated surviving his first hiccup.
Rafael Nadal progressed through to the quarter-finals with a straight sets victory over Kei Nishikori, but it was a far from comfortable outing for the world number one.
Nadal had won all five of his previous meetings against Nishikori and, while he made it six out of six today, he was pushed hard by his Japanese opponent before sealing a 7-6 (7/3) 7-5 7-6 (7/3) win at Rod Laver Arena.
The 13-time grand slam winner had not been broken previously in the tournament but dropped four of his service games before finally ending the impressive challenge of Nishikori in a match that lasted three hours and 17 minutes.
Maria Sharapova's struggles caught up with her as she followed Serena Williams out of the Australian Open.
The third seed had spent two minutes short of seven hours on court in her first three matches, half of it in extreme heat in the second round against Karin Knapp.
All appeared well when she won the first set of her fourth-round match against Dominika Cibulkova but Sharapova needed treatment for a hip problem and faded to a 3-6 6-4 6-1 defeat.
The Russian missed the latter part of last season with a shoulder problem, and she said: "Those aches and pains are expected when you spend a long time on the court. You just have to play through it. This is only my second tournament back, so it was those types of things that are expected.
"I haven't been playing the best tennis of this tournament, but I found ways to get through the last two matches. I tried to do that again today, but she played extremely well."