Novak Djokovic on Monday set a record in men's and women's tennis for total weeks spent on top of the world rankings.

The 35-year-old winner of 22 Grand Slam titles is enjoying his 378th week in pole position, edging ahead of Steffi Graf who was on top of the women's rankings for 377 weeks in her career.

"It's surreal in a way to be that many weeks world No 1, to match Steffi Graf, who is one of the all-time greats of our sport, both men and women," said Djokovic, whose first spell at the top began in July 2011 after his maiden Wimbledon triumph.

AFP Sport looks at three rankings landmarks through the decades:

? Pat Rafter: Two Slams, one week at No 1

Australia's Pat Rafter served and volleyed his way to the 1997 and 1998 US Opens, two of his 11 career titles.

Rafter was, however, plagued by shoulder trouble all his career and retired in 2001, aged just 29 with two heartbreaking defeats in Wimbledon finals unwanted memories.

Rafter was world No 1 for just a week from July 26, 1999, the first Australian man to reach the rankings summit since John Newcombe in 1971.

He took top spot from Andre Agassi and then quickly surrendered it to Pete Sampras.

Rafter remains the only player since rankings began in the 1970s to spend just one week at No 1. Next on the list are Evonne Goolagong and Carlos Moya who each spent two weeks at the summit.

"I always joke with the players. They say, 'Congratulations, mate, you made No 1.' I say, 'Yeah, one week.' They say, 'At least you bloody got it. At least you can say you got there'."