Roger Federer has added yet another record to his vast collection, becoming the oldest men's tennis world number one.
His three set win over Dutchman Robin Haase 4-6 6-1 6-1 to reach the semi-finals in Rotterdam ensures he will take the crown from Rafael Nadal.
Federer showed some early nerves in his quarter-final clash, dropping serve in the ninth game on his way to conceding the first set.
Federer first topped the world rankings in 2004 and holds the record of 302 weeks at the summit.
American Andre Agassi was the previous oldest player to be ranked world number one, in 2003 aged 33.