Andy Murray admitted his opponent was in a tough position after coasting to victory over an exhausted Gilles Simon at the Australian Open.
The Frenchman was a physical wreck after his near-five hour victory over Gael Monfils at the weekend, and Murray barely had to move out of first gear to reach the quarter-finals with a 6-3 6-1 6-3 win today.
"It was kind of tough, a tough situation for both players - more obviously for him," Murray said afterwards.
"After the first few games, it didn't feel like that competitive. At this stage of a grand slam you're sort of geed up and prepared for a tough battle.
"That's why it becomes hard because the emotions aren't quite into it. You're not quite necessarily feeling pressure, but you're wanting to try to finish the match as quickly as possible."
Despite his exhaustion Simon managed to twice break Murray at the Hisense Arena before Murray swept into the last eight to set up a meeting with Jeremy Chardy.
Serena Williams trounced Maria Kirilenko to set up an all-American quarter-final with would-be successor Sloane Stephens.
The 31-year-old Williams needed less than an hour to advance under lights at Rod Laver Arena with a 6-2 6-0 victory.
Wise-cracking 19-year-old Stephens has been touted as an heir to the 15-times grand slam champion Williams, and bolstered her own credentials with a mature 6-1 3-6 7-5 win over Serbia's Bojana Jovanovski.
But Williams fired a warning shot ahead of the generational battle, with her serve on fire and after bashing 22 winners against the 14th-seeded Russian.
"I think she's playing great," Williams said courtside of Stephens. "I think she has incredible talent, I actually admire her as well.
"I feel like I have nothing to lose and I'm just going to have fun when I play."
Stephens was just happy to advance to her maiden grand slam quarter-final, and secured a Au$250,000 (Dh961,000) payday when her shrieking opponent duffed a return into the net.
"I'm sure my mum's had, like, four heart attacks," Stephens said afterwards, raising a laugh from the crowd.
"I try to save all my money because I don't want to be old and broke. I'm still trying to save my money but I'll definitely buy something nice."
Jeremy Chardy's fairy tale run continued with a 5-7 6-3 6-2 6-2 win over 21st seeded Italian Andreas Seppi.
That secured Chardy's maiden grand slam quarter-final and ensured France would have two men in the last eight, with seventh seed Jo-Wilfried Tsonga grinding down ninth-seeded compatriot Richard Gasquet 6-4 3-6 6-3 6-2.
Unfancied and unseeded, the scruffy-bearded Chardy, ranked 36th in the world, stunned sixth seed Juan Martin del Potro in his previous match and said he had nothing to lose against Murray.
"(It's) just like a dream," the thrilled 25-year-old told reporters. "I know I can beat everybody. So when I feel confident, I believe in me. Against Del Potro, I played a very good match. So it was good for my head."
Roger Federer defused Milos Raonic's serve before clinically despatching the Canadian 6-4 7-6 6-2 to reach a 35th straight grand slam quarter-final.
The rampant Swiss gave up only five points on his first serve and hit 34 winners in the one-sided two-hour contest against the 13th seed on a cool Rod Laver Arena.
Federer wrapped up the first set when Raonic netted a volley, the second with a brilliant forehand down the line to win the tiebreak 7-4, and the third with another big forehand winner.
World number one Victoria Azarenka was back at her ruthless best in a 6-1 6-1 demolition of 47th-ranked Russian Elena Vesnina after being taken the distance in her previous match by American Jamie Hampton.
She faces a stiffer challenge in the quarter-finals against another Russian in Svetlana Kuznetsova, who sent 10th seed Caroline Wozniacki spinning out of the tournament and out of the top 10 when the next round of rankings are released.
Kuznetsova, the 2004 US. Open champion and winner at Roland Garros in 2009, spent much of last year on crutches with a knee injury, and was thrilled to secure her third quarter-final at Melbourne Park.
"If you had asked me before coming to Australia I would have laughed, definitely," Kuznetsova said of her surprising run.