Alex de Minaur has summoned every bit of his fighting spirit to win a five-set thriller against Swiss qualifier Henri Laaksonen and progress to the Australian Open third round for the first time.

The 19-year-old Sydneysider was on weary legs heading in the deciding set on Wednesday night but rallied in front of a raucous home crowd to triumph 6-4 6-2 6-7 (9-7) 4-6 6-3.

His reward for the round-two win in three hours and 52 minutes is another showdown with 17-time grand slam winner Rafael Nadal who beat him in the third round at Wimbledon last year.