Djokovic feeling the strain after late-night Medvedev
Novak Djokovic said a hard-fought fourth-round defeat of Daniil Medvedev took its toll but the world number one is confident he can recover as he strives to make history at the Australian Open.
Djokovic moved into the last eight with a 6-4 6-7 (5-7) 6-2 6-3 victory in a match which finished in the early hours of Tuesday morning on Rod Laver Arena.
The top seed and promising 22-year-old Russian Medvedev traded punches from the baseline in many a marathon rally, with Djokovic made to work as he attempts to become the first man to win the tournament seven times.
The Serbian took an akward tumble early in the third set and despite quipping in his on-court interview that he feels "fantastic" and had never been fresher in his life, as he knew next opponent Kei Nishikori would be watching, Djokovic said he was feeling the effects of a battling win.
Djokovic thanked journalists for staying late to his media conference before stating: "I had to do post-match, all of the part of my recovery program, because I didn't feel so great in the last 20 minutes of the match or so.
"So we'll see tomorrow how the body reacts, but I'm confident I can recover and I can be ready for next one."
He added: "It was not particularly the fall. It was just a little bit of fatigue, a little bit of back. Nothing major, but there are a couple of things that have surfaced, so to say, after a match like this.
"But I'll see how it goes tomorrow."
Djokovic has won all but two of his 17 matches against Nishikori, but will not be taking the eighth seed lightly after he came back from two sets down for a second time in the tournament to beat Pablo Carreno Busta.
The 14-time major champion said: "I have lots of respect for him. We did play here several times, we actually played in quarter-finals I think one year  . Every year is different, so, every match that you play against each other is different.
"I expect him obviously to come out, to try something new. I have beaten him many times that we played against each other in last couple of years and that we played on different surfaces.
"It was a couple of very close matches. I expect a tough one."