Roger Federer dominated the ATP world rankings for a record 237 weeks until August 2008, shattering the previous record set by Jimmy Connors and confirming his status as one of the game's all-time greats.

However, today Federer is playing catch-up behind his great rival Rafael Nadal, who assumed Federer's mantle shortly after defeating him in arguably the greatest of all Wimbledon finals in 2008.

The ATP's ranking system has thrown up some classic rivalries over the years, from Borg-McEnroe to Agassi-Sampras and Becker-Edberg, but arguably never one as intense or awe-inspiring as this.

The rolling ranking system requires players to defend points they have won in the equivalent tournament in the previous year – for example, if they win in Monte Carlo one year, they will drop points the following year unless they win again.

Rod Laver was unsurprisingly the first men's number one in the Open era, with global rankings not generally maintained other than on a loose annual basis during the amateur days.

Most of the game's greats held the honour at some point in their careers, but some holders were controversial, such as Thomas Muster, who won all his pre-number one tournaments on clay, and Marcelo Rios, who never won a Grand Slam title.

Today's rankings showcase the growing talent in the upper echelons of the men's game. Scotland's Andy Murray is closing in on the top two, while Argentina's Juan Martin Del Potro is another good bet to star in the seasons ahead.