The end-of-season event, open to male professional tennis players aged 21 and under, has a history of introducing new features.

This year’s event at the PalaLido, set to begin tomorrow, is no exception.

Rule changes this year include a reduced warm-up from four minutes to one, courtside coaching, limited medical time-outs of one per player per match and timed bathroom breaks up to a maximum of three minutes, with an extra two for a change of attire.

Format innovations pioneered in previous editions are also set to feature including best of five-set matches, with each set the first to four games, no advantage scoring, free fan movement, electronic line calling, a shot clock, video reviews and towel racks.

Group A features Spain’s Carlos Alcaraz, ranked number 32 in the world, Brandon Nakashima of the United States, the world number 63, Argentina’s Juan Manuel Cerúndolo, the world number 91 and Holger Rune of Denmark, the world number 109.

In Group B the line-up features Sebastian Korda of the United States, the world number 39, Italy’s Lorenzo Musetti, the world number 58, Hugo Gaston of France, world-ranked 67, and Sebastián Báez of Argentina, ranked number 111 in the world.

Round-robin action begins tomorrow, with afternoon fixtures scheduled in Group A between Nakashima and Cerundolo, followed by Alcaraz, top seed for the event, against Rune.

The evening session is set to feature the start of Group B, with second seed Korda facing Gaston, before Musetti takes on Baez.

Last year’s edition was cancelled due to the coronavirus pandemic.

Italy’s Jannik Sinner won the event in 2019.