Novak Djokovic remains on course to keep Andy Murray from the number one ranking after reaching the quarter-finals of the Paris Masters.
The Serb, 29, beat Bulgaria's Grigor Dimitrov 4-6 6-2 6-3 and needs two more wins this week to ensure he stays top of the rankings.
Should the 12-time Grand Slam champion fail to reach the final in Paris, Britain's Murray could overtake him.
The Scot, 29, takes on Frenchman Lucas Pouille in the third round on Thursday.
Murray must win the title if Djokovic fails to reach the final, although if the Serb should lose before the semis then Murray would only need to reach the final.