The 37-year-old Serbian, ten-time winner of the Australian Open, is chasing a record 25th Grand Slam title. He won 6-3, 6-4, 7-6 (7/4) and reached the quarter-finals in Australia for the 15th time, a record he shares with Swiss Roger Federer.
Djokovic will meet Alcaraz on Tuesday, who took advantage of the retirement of Briton Jack Draper (18th) on Sunday.
The winner of this quarter-final poster could then meet world No.2 Alexander Zverev, if the German overcomes the American Tommy Paul (11th).