Rafael Nadal's ascent to top spot in the world rankings will now take place next week after a surprise loss to Novak Djokovic.
The Spaniard's victory over Nicolas Lapentti at the Western & Southern Financial Group Masters on Friday ensured he would finally succeed Roger Federer as world number one this month.
Yet the French Open and Wimbledon winner needed to to win the Cincinnati tournament to supplant the Swiss immediately and his 6-1 7-5 semi-final defeat to Djokovic means he must now wait until August 18.
Nadal's loss brought a sudden end to his impressive 32-match winning streak and put the Serb through to a final showdown with British number one Andy Murray.
Djokovic made surprisingly quick work of Nadal, firing four aces and winning an astounding 76% of second-serve points.
Murray booked his place in the final with a 6-4 6-4 triumph over number 16 Ivo Karlovic. It is the 21-year-old Scot's first championship final since winning his second title of year at Marseille in February.
Murray is in good form having reached the semi-finals in Toronto last week and the last eight at Wimbledon. Coincidentally, he was eliminated from both of those events by Nadal, who has not lost to Murray in five meetings.
