Novak Djokovic moved to the brink of the last four at the ATP Finals with a comfortable victory over Andrey Rublev in Turin on Wednesday.
The world number one, bidding to equal Roger Federer's record of six titles at the season-ending event, brushed aside fifth seed Rublev 6-3, 6-2.
Djokovic will be sure of his place in the semi-finals if Norway's Casper Ruud beats British alternate Cameron Norrie later in the day.
The 34-year-old Djokovic is looking to cap off a remarkable year which saw him only just miss out on completing a calendar Grand Slam with defeat by Daniil Medvedev in the US Open final.
He sits top of the Green Group and plays Norrie in his last round-robin match on Friday.