The math is fairly simple (although round-robin math is never QUITE that simple).
Alexander Zverev beats winless Hubert Hurkacz – and he’s in.
Even if Jannik Sinner were to upset Daniil Medvedev in the night session, both Medvedev and Zverev would beat him out because even though they would be 2-1, they played the full complement of three group matches to Sinner’s two.
He came close to winning anyway, in what was a meaningless match full of meaningful effort.
ATP Tour Finals
Location: Turin, Italy
Dates: Nov. 14 – 21, 2021
Prize money: $5,000,000
Draws: RR 8S – 8D
Thursday, Nov. 18, 2021
 Nikola Mektic / Mate Pavic (CRO) def.  Ivan Dodig (CRO) / Filip Polasek (SVK) 64 76 (6)
 Kevin Krawietz (GER) / Horia Tecau (ROU) def  Marcel Granollers (ESP) / Horacio Zeballos (ARG) 63 67 (1) [10-6]