After a shaky start, the 29-year-old broke his No. 122-ranked opponent twice in each of the second and third sets to win the match.
The former US Open champion hit 13 winners but also recorded 30 unforced errors which allowed his Italian opponent to take advantage.
Carlos Alcaraz, the current champion, is the tournament's top seed and is arguably the favourite to win it.
Andrey Rublev has not been in good form recently having lost four of the last five matches he has played. He will look to bounce back in style by picking up a win against his much...
Thiem became the first male player born in the 1990s to claim a Grand Slam singles title, as well as the first Austrian to win the US Open singles title.
The Diriyah Tennis Cup is an exhibition competition that will take place outside of Riyadh, the Saudi Arabian capital.
Tommy Paul and Dominic Thiem are scheduled to face one another in the first round of the 2022 ATP Vienna Open on Tuesday, October 25.
Hubert Hurkacz and Dominic Thiem are scheduled to face each other in the quarterfinal round of the 2022 ATP European Open on October 21.
Dominic Thiem and Francisco Cerundolo are scheduled to face each other in the second round of the 2022 ATP European Open on October 20.
Botic Van De Zandschulp and Dominic Stricker are scheduled to face each other in the first round of the 2022 ATP European Open on October 18.