The final grand slam of the season is on the horizon as the world's top tennis players head to Flushing Meadows for the US Open.

Rafael Nadal and Sloane Stephens were victorious last year, but they have been challenged by others for the top honours in 2018, with a number of contenders looking to head towards the end of the year on a high.

Roger Federer, now 37, could make history as he chases major title number 21, as could Serena Williams, 36, as she returns after missing last year's tournament to give birth to her first child.

Here, we bring you the best Opta facts from both the men's and the women's singles draw.

Men's singles

1 - The US Open is the only men's grand slam that has not seen a player win in the Open Era without dropping a set en route to the title.

2 - Nadal could become just the second player in the 21st century to retain the men's singles title after Federer, who won five times between 2004 and 2008.

5 - Federer's run of consecutive titles represented a joint record at any grand slam in the Open Era (also Nadal 2010-14 French Open, Bjorn Borg 1976-80 Wimbledon, Federer 2003-07 Wimbledon). Only Jimmy Connors and Pete Sampras can match Federer's total of five titles.

12 - The number of years since an American reached the men's US Open final, when Andy Roddick lost to Federer in 2006.

13 - Of the last 14 men's singles winners, 13 have been European. Juan Martin del Potro of Argentina in 2009 was the exception.

37 - Federer would become the oldest men's winner in the Open Era if he claimed the title, surpassing Ken Rosewall in 1970 (35 years, 10 months, 11 days). Sampras was the youngest champion (19 years, 28 days).

Women's singles

5 - The number of women to follow up a final defeat at Flushing Meadows by winning the US Open title the following year. Madison Keys will hope to follow in the footsteps of Chris Evert, Martina Navratilova, Steffi Graf, Serena Williams and Justine Henin.

6 - Stephens could become the sixth American player to win at Flushing Meadows in consecutive years in the Open Era.

8 - Serena Williams has reached at least the semi-finals in each of her previous eight appearances at the US Open, last falling short of that mark in 2007.

10 - The number of all-American women's singles finals in the Open Era - including last year's clash, between Stephens and Keys.

36 - Both Serena and sister Venus (38) could become the oldest women's champion, with Flavia Pennetta (33 years, 6 months, 18 days) currently holding the record. The youngest winner was Tracy Austin (16 years, 8 months, 28 days).

2011 - The last time a European woman won back-to-back grand slams, with Kim Clijsters triumphant at Flushing Meadows in 2010 and then winning the Australian Open. Wimbledon champion Angelique Kerber could achieve the same feat.