Alex de Minaur is the only teenager in this week's elite Next Gen ATP Finals after a breakout 2018 campaign for the Australian.
The 19-year-old will face Italian wildcard Liam Caruana in his opening round-robin match in Milan on Wednesday and is the highest ranked player in Group B.
Starting the year ranked 208, de Minaur is at a career high of 31 after a year in which he was runner-up at the Sydney International in January and August's Washington Open.
"I definitely wasn't expecting this," De Minaur told the ATP World Tour website.
"It's been a great year, I've played some unbelievable tennis."
The Sydney-born baseliner will hope that form continues with group matches against American Taylor Fritz and last year's inaugural Next Gen finalist Andrey Rublev certain to test him.
In their only meeting to date, De Minaur saved four match points in a second-set tiebreaker before he overcame Rublev in an almost three-hour semi-final battle in Washington.
The top seed for the event is Stefanos Tsitsipas, who became the first Greek to win an ATP Tour event with his victory in Stockholm last month.
The 20-year-old is ranked world No.15 and will face Spain's Jaume Munar, Frances Tiafoe (US) and Poland's Hubert Hurkacz in Group A.
Each player will contest three matches with the top two from each group to progress to the semi-finals.
Scoring at the 21-and-under event will be over shorter four-game sets and tie-breaks (three-all) in best of five-set encounters, with no-ad scoring.
Players can also communicate with coaches in-match via headsets.
In another innovation at the tournament, this year players will be instructed to use towel racks which will be positioned at both back sides of the court rather than relying on ball kids to retrieve and handle the sweaty towels.
