Roger Federer sealed a return to the top of the tennis world rankings for the first time in more than five years by winning his quarterfinal at the ABN AMRO World Tournament on Friday.
Beating leading Dutch player Robin Haase 4-6, 6-1, 6-1 means the 36-year-old Federer becomes the oldest man to top the world rankings, surpassing Andre Agassi, who held the record at age 33.
Federer will leapfrog 31-year-old Rafael Nadal to No. 1 when the rankings are updated on Monday.
Also a record will be the five-years-plus which have elapsed since Federer was last No. 1.
On Monday, he will extend his record of 302 weeks at No 1 since the rankings began in 1973.
Federer, the 2005 and 2012 ABN AMRO champion, plays either Andreas Seppi or Daniil Medvedev in the semifinals on Saturday.
Haase made clear he was going to make Federer fight, and broke him in the ninth game and fired an ace to take the set 6-4.
But Federer stepped up a gear and blew Haase away in the second set, reeling off 11 straight points to race to 3-0 in taking the set 6-1.
Federer then broke Haase twice early in the third for 3-0, and swept to the victory.
Earlier, Grigor Dimitrov beat Andrey Rublev 6-3, 6-4 to reach the semifinals, where he will meet David Goffin, who progressed when his quarterfinal opponent Tomas Berdych pulled out sick.