From one No.1 to another (Serena WIlliams just administered a bruising defeat to Margarita Gasparyan, in case you've not been with us), up next we have Novak Djokovic playing Frenchman Gilles Simon, ranked 15th in the world.

Watch full highlights of the match:

GAME, SET AND MATCH! - DJOKOVIC 6-3 (1) 6-7 6-4 4-6 6-3 SIMON. Finally! Djokovic books his place in the last eight after a tremendous tussle with Simon. The Frenchman can't make any inroads on the Serb's serve this time, as he sees it out with aplomb at the second time of asking. A sizzling backhand winner seals it to love after four hours and 32 minutes of pulsating tennis. Simon gets huge applause for his role in the match but it's Djoker who progresses to his 27th straight Grand slam quarter final where he will meet Kei Nishikori.

BREAK! - DJOKOVIC 6-3 (1) 6-7 6-4 4-6 5-3 SIMON. The crowd erupts once more as Novak can't complete the job. The Serb has two match points but his opponent doesn't want to go home just yet. He's helped by Djoker, who clocks up 100 unforced errors on his way to losing the game.

BREAK! - DJOKOVIC 6-3 (1) 6-7 6-4 4-6 5-2 SIMON. Gilles stuns the Rod Laver Arena by pulling one break back! Everyone thought it was done and dusted but the Frenchman has hit back to give himself a glimmer of hope. At 0-30 he just misses a crosscourt attempt on the run. It seems his chance is over, but a hopeful challenge pays off and gives him two break points. Nole saves one but can't shake off his opponent who has the crowd on their feet as he takes the game. Surely he can't, can he?!

BREAK! - DJOKOVIC 6-3 (1) 6-7 6-4 4-6 5-1 SIMON. It's gone terribly wrong for Gilles. Another capitulation under the searing stare of the world number one sees him broken to 15. Djoker to serve for the match. How many times have we seen Djokovic taken to a fifth, only to run away with it in what should be a tense situation?

DJOKOVIC 6-3 (1) 6-7 6-4 4-6 4-1 SIMON. Novak is completely reinvigorated. He makes short work of Simon, finihsing off the game to 15 with a sizzling crosscourt forehand that the Frenchman can't get back. The Serb consolidates and looks odds-on to progress now after a titanic battle.

BREAK! - DJOKOVIC 6-3 (1) 6-7 6-4 4-6 3-1 SIMON. Heartbreaking for Simon. The Frenchman looked in control at 40-30 but allowed Djoker the chance to set his sights at deuce. The Serbinator has a knack for benefiting from a player's nerves and he duly makes it count when his opponent lashes long to give the top seed a real gift.

DJOKOVIC 6-3 (1) 6-7 6-4 4-6 2-1 SIMON. The world number one looks to have re-focused at just the right time. A love hold makes it eight points on the spin on serve and the Frenchman is back under the spotlight all to quickly form his perspective.

DJOKOVIC 6-3 (1) 6-7 6-4 4-6 1-1 SIMON. The match passes the foour-hour mark and Simoon is very much in with a shout of pulling off the major upset here. Djoker tries to crank up the heat but Gilles isn't about to let an early lapse in the fifth destroy all of his hard work. It's a hold to 30 and anyone's from here.

DJOKOVIC 6-3 (1) 6-7 6-4 4-6 1-0 SIMON. Nole dusts off the cobwebs and the dismay of that fourth-set disappointment to produce a competent hold to get off to a strong start in the decider.

Djokovic 6-3 6-7 (1-7) 4-6 Simon. Djokovic attempts to deploy a dropshot , but once again it's no good. He's had 83 unforced errors in this game, which is probably at least in part why it's been so horrible to watch. The fourth set goes to Simon.

Djokovic 6-3 6-7 (1-7) 4-5 Simon. Looking increasingly like we'll be going in to another set. now.

Djokovic 6-3 6-7 (1-7) 6-4 4-4 Simon. We're still on serve in the Fourth set, it's hard to imagine how this match is going to be resolved after 3 and a half hours on court. Djokovic's serve is powerful, but you'd be forgiven for wondering why he hasn't got anything else up his sleeve.

Djokovic 6-3 6-7 (1-7) 3-3 Simon. This is not a lot of fun for anybody involved, I suspect, In the player's box, Boris Becker is visibly shaking. WIth what? Nerves? Anger?

Djokovic 6-3 6-7 (1-7) 6-4 1-1 Simon. As this game started, I felt quite enthusiastic about the prospect of rallies. Surely there's a happy medium between this and the ruthless efficiency of Serena Williams?