Alcaraz will finish the year at the top of the rankings for the second time, having become the first teenager to achieve that feat in 2022.
In addition to his tour-leading 70 wins, Alcaraz has also claimed an unrivaled eight titles in 2025, including two Grand Slams, equal to his total number of losses.
He will now look to complete another impressive season by winning the ATP Finals for the first time.
Musetti was backed by a passionate home support inside a 12,000-capacity Inalpi Arena as he looked to build on the momentum of his dramatic victory over De Minaur on Tuesday.
The Italian, battling fatigue in his seventh match in nine days after reaching the Athens Open final, matched Alcaraz in the first set, but his admirable resilience eventually ended in an absorbing 11-minute tenth game.
Although Musetti continued to press, resisting a break point in his first service game of the second set, his relentless opponent continued to apply pressure and broke at love for a 3-1 lead.
That sparked Alcaraz’s run to the finish line, but only after Musetti, with a free hit, created his first two break points to revitalize the crowd.
That excitement was short-lived as Alcaraz hit back with four straight points, and there would be no recovery for a fading Musetti, who lost serve again before Alcaraz cruised to victory to achieve the first of his goals in northern Italy.
