Italian suffers an injury during his opening match in Turin on Sunday.

Matteo Berrettini and Alexander Zverev embrace after Berrettini retires from their Nitto ATP Finals match.

Matteo Berrettini will begin his 2021 Nitto ATP Finals on Sunday evening against Matteo Berrettini.

Andrey Rublev, Alexander Zverev, Matteo Berrettini, Novak Djokovic, Daniil Medvedev, Stefanos Tsitsipas, Casper Ruud and Hubert Hurkacz walk towards the Piazza San Carlo in Turin

Matteo Berrettini will try to thrill his home fans in Turin during his second appearance at the Nitto ATP Finals.

Matteo Berrettini breaks once to secure a 7-6(3), 6-3 victory in the first round over qualifier Alexei Popyrin at the Erste Bank Open.

INDIAN WELLS, CA - OCTOBER 10: Matteo Berrettini of Italy at the BNP Paribas Open held at the Indian Wells Tennis Garden on October 10, 2021 in Indian Wells, California (Photo by Peter Staples/ATP Tour)

Matteo Berrettini moves on to the third round in Indian Wells Sunday with a straight-sets victory over Alejandro Tabilo.

Matteo Berrettini battles past Felix Auger-Aliassime on Friday in Boston to take a 3-1 lead in their ATP Head2Head series.

Team Europe and Team World gather in front of the Boston skyline at LoPresti Park on Wednesday ahead of the Laver Cup.

Casper Ruud, Stefanos Tsitsipas, Daniil Medvedev, Alexander Zverev, Matteo Berrettini and Andrey Rublev pose with Team Europe Vice Captain Thomas Enqvist.

Sixth seed Matteo Berrettini overcomes qualifer Oscar Otte on Monday at the US Open to reach his fourth major quarter-final.

Matteo Berrettini began Saturday as one of three Italian men (Sinner, Seppi) in the US Open third round, the most in tournament history.

Matteo Berrettini hits 50 winners in his four-set victory against Corentin Moutet on Thursday.

Matteo Berrettini defeats Jeremy Chardy in straight sets on Tuesday to reach the second round of the US Open.

Italy's Matteo Berrettini will miss the Tokyo Olympics due to a thigh injury sustained at Wimbledon.

Matteo Berrettini poses with the Italian football team that won the European Championships in London on Sunday.

Matteo Berrettini with Sergio Mattarella, the Italian President, and Italian football captain Giorgio Chiellini in Rome on Monday.

Matteo Berrettini was edged out by Novak Djokovic on Sunday at Wimbledon in his first Grand Slam final.

Matteo Berrettini recovers from 2-5 down in the first set against Novak Djokovic in the Wimbledon final on Sunday.

Matteo Berrettini celebrates reaching the Wimbledon final on Friday as he walks off Centre Court.

Matteo Berrettini hits 60 winners in a four-set victory against Hubert Hurkacz in the Wimbledon semi-finals.

Matteo Berrettini hits 33 winners in a four-set victory against Felix Auger-Aliassime in the Wimbledon quarter-finals.

Matteo Berrettini beats Felix Auger-Aliassime to reach the Wimbledon semi-finals and take a 2-0 lead in their ATP Head2Head series.