De Minaur, who is ranked fifth in the competition and 29th in the world, admitted that luck was on his side during the match at Sydney Olympic Park Tennis Centre that had to be postponed to Wednesday due to rain, reports Efe.
"Reilly is an incredibly tough opponent and it's pretty hard to get that serve back. I would have loved to get that break in the second. I had a couple of chances," De Minaur said.
"I did well to focus on my serve and I'm glad things went my way today," he added.
De Minaur will now face fellow countryman Jordan Thompson on Thursday.
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