Defending champion Novak Djokovic is through to the last eight of the Australian Open but only after surviving a huge test from local favourite Lleyton Hewitt at Rod Laver Arena in the early hours of Tuesday morning.
Hewitt gave the world No.1 his stiffest test to date despite amazingly dropping his first five service games, Djokovic having conceded only 10 games in total in brushing aside Italian Paolo Lorenzi, Colombian Santiago Giraldo and Frenchman Nicolas Mahut.
And as always there was a trademark Hewitt rearguard as he launched one final counter-punch from 1-3 down in the third set to take the duel to a fourth set, but Djokovic was equal to the challenge despite having been broken four times as he won 6-1 6-3 4-6 6-3.
Djokovic will now meet Spanish fifth seed David Ferrer, who, after comfortably accounted for 17th-seeded Frenchman Richard Gasquet, finds the tournament top seed standing in his way of a semi-final berth for the second year in a row.
But the biggest upset of the men's draw so far was undoubtedly Kei Nishikori's five-set defeat of French No.6 seed Jo-Wilfried Tsonga, the 24th seed becoming the first Japanese player to reach the last eight at the Australian Open in 80 years.
Having now won two five-setters here, after coming back from two-sets-to-love down to beat local Matthew Ebden in the second round, Nishikori will have to step up even further to beat British No.4 seed Andy Murray, who benefitted from an early finish against Kazakh Mikhail Kukushkin.
The early signs were all bad for Hewitt as he dropped his first two service games to fall behind 4-0 and though he gave the packed Rod Laver Arena crowd something to cheer about when he retrieved one of the breaks, he would eventually drop the set in 31 minutes.
It wasn't until he served for the sixth time in the match that Hewitt was able to hold, by which time he was behind again despite claiming another break of his own, and after 75 minutes he was two sets adrift.
Djokovic looked set to move in for the quick kill when he opened up a 2-0 lead in the third set but against the run of play Hewitt hit back in the fifth game and then broke again in the ninth before serving it out to force a fourth set.
And he then had the chance for a fifth break in the third game of the fourth set but couldn't capitalise, with Djokovic finally reclaiming the ascendancy in the sixth game before holding serve in the ninth game to seal his win.
Earlier, Nishikori set up a debut Grand Slam quarter-final against Murray, but the nature of the pair's wins could not have been more contrasting with Nishikori enduring a 210-minute minute torture test in the Melbourne heat, while Murray progressed in just 48 minutes after Kukushkin retired.
Nishikori's 2-6 6-2 6-1 3-6 6-3 win was his second five-set victory of the tournament and gives him a shot at Murray, who has dropped just one set for the tournament so far and has won the only previous encounter between the two.
Murray had ripped through the first two sets and conceded just two games but when he broke the Kukushkin serve in the opening game of the third to take a 6-1 6-1 1-0 lead, the world No.92 called