Novak Djokovic showed his determination to remain at the top of the world rankings by coming from a set down to beat Grigor Dimitrov and reach the quarter-finals of the Paris Masters.
The top seed will be guaranteed to fend off Andy Murray in the battle for the number one spot at least until the ATP World Tour Finals if he progresses to the final in the French capital and is the Serb is just two wins from achieving that after a 4-6 6-2 6-3 victory over Dimitrov.
Twelve-time grand slam champion Djokovic required treatment on his right knee in the second set, but turned the tide after Dimitrov had threatened to dump him out with an inspired performance in the first set.
The 14th seed from Bulgaria broke twice to take an opening set in which he won 85 per cent of points on his first serve and unleashed an array of classy winners to put the favourite on the back foot.
But that was as good as it got for Dimitrov, who paid the price for making too many unforced errors as the clinical Djokovic raced into a 3-0 lead in the second set and never looked back.
Djokovic, attempting to win this tournament for a fourth year in a row and a fifth time in total, dictated the final set and the defending champion will now face Marin Cilic in the last eight.