World number one Jannik Sinner brushed past Alex de Minaur after Taylor Fritz defeated an irate Daniil Medvedev on the opening day of the ATP Finals.

Sinner, playing on home soil in Turin, Italy, won 6-3 6-4 to extend his perfect record against the Australian seventh seed.

Earlier, American Fritz recorded his 50th win of the year by beating Medvedev 6-4 6-3 as the group stage of the season-ending tournament got under way.

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

Fourth seed Medvedev hit seven double faults in a tight opening set in the Ilie Nastase Group, including two back-to-back to give Fritz set point.

Capping a calamitous service game, the Russian double-faulted again, and reacted angrily to going behind by smashing his racquet against his seat and the ground.

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

Further break points went unconverted for both players before fifth seed Fritz, 27, capitalised on his third, with a mis-hit lob that landed on the baseline.

An irritated Medvedev then received a point penalty after he broke a courtside microphone by throwing his racquet.