Two-time defending champion Sinner blitzed through the opening set against Duckworth, then withstood a second-set resurgence from the veteran before wrapping up the match 6-1 6-4 6-2 on Thursday night.
"First of all every match is very difficult, so I'm very happy to be in the next round," Sinner said.
"I feel like I was returning very, very well today, also serve was really good today, so I'm very happy about my performances.
"I feel like I'm in good shape at the moment ... I'm very happy, I know how much work we put in, so the body feels good, also the mind is in a good moment.
"First tournaments are also special for all of us, and there's nowhere better to start a season. A very special tournament for me and a very special court this has been for me ... let's see what's coming this year."
Sinner next faces American world No.85 Eliot Spizzirri for a spot in the second week.
"I've been watching him, also last year a little bit," he said.
"These kinds of players are very aggressive on the court, big, big server also ... let's see what's coming
"I don't know him as well obviously, we haven't played yet.''
Ahead of Thursday night's match, world No.88 Duckworth leaned into the knowledge he'd beaten Sinner in the past - albeit when the Italian was a rangy teenager back in 2021.
But this was not the same Sinner and the world No.2 made that clear as he polished off the first set in just 25 minutes.
To his credit, Duckworth fought back in the second set.
But Sinner broke the Australian at 3-3, then professionally saw out the set in 42 minutes.
Sinner raced away to claim the first three games of the third set, then saved two break points to go up 4-0.
Duckworth made the Italian serve out the victory, which he did with aplomb.
"I know he had so many surgeries in his past and it's great to see him competing at the highest level, so I wish him only the best for the rest of the season," Sinner said.
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