Jack Draper looks to cap breakthrough season at Next Gen ATP Finals

WATCH: Draper scored his first Top 5 win over Stefanos Tsitsipas earlier this summer in Canada.

Jack Draper's season began quietly at the lowest levels of the ATP Challenger Tour, but the 20-year-old from Great Britain has announced his arrival loudly since then, climbing more than 200 spots to stand on the cusp of the Top 40 in the rankings.

This week, he's the second-highest player at the 21-and-under Next Gen ATP Finals in Milan, though only following the withdrawals of Carlos Alcaraz, Jannik Sinner, and Holger Rune.

Even he's a little surprised by his rapid rise.

"A year ago, I was at a club in Germany playing a Challenger level event, trying to grind my way up and I've now been able to play on big stages. There would definitely have been an element of surprise back then if you had told me that I would be Top 50 in the world," Draper told the Daily Mail.

Getting his first ATP win as a Madrid wildcard, he reached the quarterfinals of Montreal as a qualifier and the third round of the US Open, scoring wins against Top 10 players Félix Auger-Aliassime and Stefanos Tsitsipas.

Playing a tight three-setter against No.1 Carlos Alcaraz in front of a packed crowd at the ATP 500 in Basel was also a big occasion.

"But the experience of playing these guys has shown me I'm not that far off. That's the biggest lesson of this year, plus the things I need to get right, maybe start being more aggressive and physically getting stronger," said the son of former LTA chief Roger Draper.

During the off-season, he plans to work on his fitness to avoid problems during best-of-five contests like he had during Wimbledon.

"That's very important, because there's a limit to what you can do when you are playing matches," Draper said.

He's also building different parts of his game. The big-hitting 6'4" player recalls having to be a good mover in the juniors, when he was a lot smaller, and still considers that a strength for his size.

"I can scrap around the court a bit like when I was younger," said Draper, adding that his priority is improving his already-good serving. "I want to hit my spots better and get my average higher."

This is his first appearance at the Next Generation ATP Finals.