Roger Federer becomes oldest world No 1 in tennis history

Roger Federer became the oldest world number one on Friday as he defeated his opponent to enter the semi-final of the ABN Amro World Tennis Tournament in Rotterdam.

Roger Federer had entered thequarter-final after defeatingGermany's Philipp Kohlschreiber and clashed the former number one Dutchman Robin Haase.

The 36-year-old Swiss overcame an early setback to beat Robin Haase of the Netherlands 4-6, 6-1, 6-1 and will replace old rival Rafael Nadal at the top of the rankings.

Here is what is tweeted after reaching number one spot.

"What an amazing run it's been, to be number one again means a lot to me," Federer said.

"This is incredibly special, I'm so happy. I didn't really think I could get back to number one, this is a significant moment in my career."

Federer surpasses Andre Agassi, who held the top spot aged 33 years and 131 days in 2003, as the oldest man to claim the world number one spot.

It is Federer's first time back at the summit since October 2012 having first claimed the top position in February 2004.

"Reaching number one is the ultimate achievement in tennis. When you're older you have to work double the amount, you have to wrestle it back from someone who's also worked hard to get there. It's a dream come true," added an emotional Federer.

"It's been an amazing journey and to clinch it here, where I got my first wildcard in 1998, means so much."