Shelton plans to ride on 'rowdy' Melbourne crowd to stun Sinner
The United States eighth seed beat 12th-seeded Norwegian Casper Ruud to book a clash with Italy's Sinner on Wednesday.
The 23-year-old Shelton revels in the atmosphere at Melbourne Park, where he reached the semi-finals last year only to lose in straight sets to Sinner.
"I'm definitely a competitor, I'm rowdy on court, I look forward to rowdy crowds, and down here in Australia there's no shortage," he said after seeing off Ruud in four sets in Monday's late-night match at Rod Laver Arena.
Shelton found himself on centre court after Novak Djokovic's last-16 encounter with Jakub Mensik fell by the wayside when the Czech player pulled out injured.
Some fans were disappointed not to see 10-time Australia champion Djokovic -- something Shelton was aware of.
"I want to thank you guys for staying out here so late," he told the arena in his on-court interview afterwards.
"I know you guys were probably looking forward to watching Novak tonight," he added, to cheers and a couple of boos.
"I actually heard it from the stands, but I hope we didn't disappoint with that match."
Shelton celebrated beating Ruud with his trademark "dialled in" motion of pretending to slam down a landline telephone.
Sinner and Shelton have met nine times, with the world number two winning eight of them.
Shelton's only victory over the four-time major winner came in their first encounter, in 2023.
But in a warning to Sinner, Shelton said: "I have a lot more to do here and a lot more to improve."