Roger Federer, already the holder of a record 17 Grand Slam titles, reached another landmark on Monday when he celebrated an unprecedented 287th week as world number one.

The Swiss legend, who turns 31 in August, had pulled level with Pete Sampras's record of 286 weeks when he reclaimed top spot after a two-year absence following his seventh Wimbledon title last week.

With the Olympics and US Open fast approaching, Federer shows no sign of his passion for the game waning despite being the second oldest man after Andre Agassi to hold the world number one ranking.

"I'm so happy I'm at the age I am right now, because I had such a great run and I know there's still more possible," said Federer.

"To enjoy it right now, it's very different than when I was 20 or 25. I'm at a much more stable place in my life. I wouldn't want anything to change. So this is very, very special right now."

Federer holds a 75-point lead over world number two Novak Djokovic and is guaranteed to hold the top ranking heading into the London Olympics.

He now has a tour-best five titles in 2012, including his 20th Masters crown in Madrid in the run-up to the French Open.

Federer has compiled a 63-6 match record since last year's US Open, going 17-0 at the end of 2011 and is 46-6 this season.

Despite equalling Sampras's record of seven Wimbledon titles, Federer believes it wasn't just his victory at the All England Club over Andy Murray in the final that enabled him to return to the top.

He believes it was due to a series of highs and lows, notably a heartbreaking loss to Djokovic in the US Open semi-finals last September where he had been two sets to love ahead with match points.

"I think it was a time where I just had to believe that things were going to turn around for me," said Federer.

"I think when I came back to Basel (last autumn), which was a home tournament, things obviously changed for me to winning ways again.

"Then the confidence rose as I went to Paris and also to London (where he won the World Tour Finals). I think this is when I realised a lot is possible in 2012."

Federer first took the world number one spot in February 2004 and held it until August 2008.

He reclaimed it in July 2009 before being deposed by Rafael Nadal after the 2010 French Open.