Canada's Felix Auger-Aliassime set up a semi-final with world number one Carlos Alcaraz by beating Germany's Alexander Zverev in the final group match of the ATP Finals.
Neither player was at their best in what was a must-win match, sharing 55 unforced errors, but two-time champion Zverev was left to rue failing to convert any of his four break points as Auger-Aliassime held his nerve to win 6-4 7-6 (7-4) and secure second place in the Bjorn Borg Group behind Jannik Sinner.
The Italian, the defending champion, had defeated already-eliminated Ben Shelton 6-3 7-6 (7-3) earlier on Friday to maintain his 100% record and extend his winning run to 13 matches.