Matteo Berrettini reportedly woke up feeling better than he expected, in terms of the abdominal injury that forced him to retire against Alexander Zverev in his first match.
But relatively early on, he announced he was a no-go. And 20-year-old countryman Jannik Sinner stepped up and trounced Hubert Hurkacz in his ATP Tour Finals debut match.
ATP Tour Finals
Location: Turin, Italy
Dates: Nov. 14 – 21, 2021
Prize money: $5,000,000
Draws: RR 8S – 8D
Tuesday, Nov. 16, 2021
 Ivan Dodig (CRO) / Filip Polasek (SVK) def.  Kevin Krawietz (GER) / Horia Tecau (ROU) 76 (2) 75
 Marcel Granollers (ESP) / Horacio Zeballos (ARG) def  Nikola Mektic / Mate Pavic (CRO) 64 76 (4)