The 19-year-old Rune, who competed in Milan last year, surged to his first ATP Masters 1000 title on Sunday at the Rolex Paris Masters. The teen will be the first alternate at the Nitto ATP Finals in Turin.

Arnaldi will join the Green Group at the 21-and-under season finale, which will also feature Brandon Nakashima, Jiri Lehecka and Francesco Passaro. The Intesa Sanpaolo Next Gen ATP Finals begins on Tuesday at the Allianz Cloud.

The 21-year-old Arnaldi has soared up the Pepperstone ATP Rankings the past two seasons, climbing nearly 900 places. The Italian won his first ATP Challenger Tour title this season in Italy and also reached Challenger finals in San Marino and France. 

Arnaldi is one of three Italians in the field with fellow home favourites Lorenzo Musetti and Passaro also competing. The trio will try to join Jannik Sinner as Italian Intesa Sanpaolo Next Gen ATP Finals champions.