The Serb beat 31st seed Verdasco 7-6 (10-8) 6-3 6-4 in an entertaining contest on Rod Laver Arena to set up a meeting against Luxembourg’s Gilles Muller for a place in the quarter-final.
Djokovic, who is the favourite for his fifth Australian Open title following Roger Federer’s shock exit in Friday’s third round, made just two service breaks.
Verdasco, who had beaten Djokovic in four of their previous 10 encounters, failed to get a service break in the Serb’s 16 service games.
The seven-time Grand Slam champion hit 43 winners and showed exquisite touch around the net while serving at a high 73 per cent.
Djokovic’s serving was a feature, winning 82 per cent of his first serves against the former??top-10 player.
The Spaniard had taken Rafael Nadal deep into the night in a five-hour, five set marathon during the 2009 semi-finals in Melbourne and he??harassed Djokovic at the start but once the Serb sealed the first set tie-break after an hour of the tense baseline battle he ran away with the match. ????
“I did serve well and that helps when you are playing big servers like Fernando, who put a lot of pressure on your service games, so you have to stay composed and hang tough,” Djokovic said.
“I tried to go more for accuracy and precision and allow myself to have an easy first ball and managed to have a lot of free points, which definitely helped.
“Physically, I feel fit now and I’m always motivated to play well in Australia and this is my most successful Grand Slam.”