Taylor Fritz kept his cool against an angry Daniil Medvedev to win the opening match of the ATP Finals in straight sets.

American Fritz recorded his 50th victory of the year by beating Medvedev 6-4 6-3 at the season-ending tournament in Turin, Italy.

Medvedev, the Russian fourth seed, broke one racket in response to his poor serve and threw a second after an unlucky shot as he lost the point.

“I’m super happy with the way I played today,” said Fritz, who reached his first Grand Slam final at the US Open in September.

Medvedev committed seven double faults in a tight first set, including two in a row to give fifth-seeded Fritz a set point.

Closing out a calamitous service game, the Russian double-faulted again and reacted angrily to being behind by smashing his racket against his seat and the floor.

At the start of the second set, Medvedev got his first break point of the match but slammed his backhand return into the net.

Further break points went unconverted for both players before Fritz took advantage of his third, with a poorly hit lob that landed on the line.

An irritated Medvedev then received a penalty point after breaking a microphone on the court by throwing his racket.

As his behavior deteriorated, he was booed by the crowd for his antics, including holding his racket by his head while waiting to receive a serve.