The Serbian world number two, despite trouble with his contact lenses, he is targeting an eighth Melbourne Park crown and 17th Grand Slam title.
The six-time champion's reward is a showdown against either long-time rival Novak Djokovic or big-serving Canadian Milos Raonic.
"It is quite unreal to be two match points down to come back and strange to play a tie-break at 12-12. I was hoping to get to the tie break," he said....
Djokovic, twice a champion in the principality, lost serve five times in a 6-3, 4-6, 6-2 defeat by Russia's 10th seed Medvedev.
The Serb was in total control on his own delivery and won his first four service games without conceding a single point
The Serbian star led a parade of the top four seeds into the last eight.
"I would like to try and stay there, obviously. It's taken a huge effort the last five, six months to get there."
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