The Italian stunned Novak Djokovic in the ATP Finals round-robin stage and beat the 36-year-old again in both singles and doubles at the Davis Cup, where he led Italy to a memorable triumph in November.
Sinner, who reached the 2022 quarter-finals at Melbourne Park, warmed up for the first Grand Slam of the year with a couple of exhibition matches ahead of his first-round match against Botic van de Zandschulp.
"I'm here to play, at least to try to play, some good tennis. Obviously it's tough to say how the season will go," Sinner told reporters.
"At the end of the year I played really good. I have still the confidence inside me, for sure. Every season is different. Every tournament is different.
"Honestly, I missed being a little bit out of competition in the last one and a half, two months or so, maybe less. It's good to be back here, to have the connection with the crowd and everything."
Sinner said he was not heading into the tournament, which starts on Sunday, completely undercooked having only taken a week off after the end of last season before beginning his preparations for 2024.
"We tried to figure out if this could be an option for the upcoming years, if this helps for me or not," Sinner added. "I played a couple of matches at the Kooyong Classic. They're not official matches but you get this match feeling a little bit.
"Let's see. We will have all the answers on Sunday, then we see how it goes. But I feel quite confident to be ready for some good tennis."
