American Brandon Nakashima beat Czech Jiri Lehecka to lift the Next Gen ATP Finals tennis trophy in Milan on Saturday.
Nakashima, ranked 49, beat 74th-ranked Lehecka 4-3 (7/5), 4-3 (8/6), 4-2 in the tournament which features the eight best players aged 21-years-and-under on the ATP Tour.
The 21-year-old, who won his first ATP title this year in San Diego, succeeds Spaniard Carlo Alcaraz who triumphed in the Next Gen tournament last year and went on to claim the US Open trophy last September.
Alcaraz, 19, became the youngest men's world number one after his US Open victory and would have participated in the ATP Tour Final which starts in Turin on Sunday and not the Next Gen, but withdrew because of an abdominal tear.
Dane Holger Rune, 19, winner of the Paris Masters and now ranked 10th in the world, preferred to be an alternate at the ATP Tour Final rather than compete in the Next Gen event.