Can anyone deprive Serena of calendar slam?
Serena Williams is about to embark on another US Open campaign but who might be the players to challenge her dominance?
The question ahead of the US Open is whether anyone can beat Serena Williams in a Grand Slam?
The world number one will soon turn 34 but shows no signs of slowing down and, ahead of the US Open, she has history in her sights.
She is already the defending champion and has achieved the so-called 'Serena Slam' - holding all four majors at the same time.
Now however, she is aiming for the calendar slam, winning all four in the same year, a feat last achieved by Steffi Graf back in 1988.
It is also the legendary German who holds records that Williams will be looking towards in the coming days as Graf achieved 22 Grand Slam singles titles, a record in the Open era, and Williams is now just one behind on 21.
Also, no woman since Graf in 1989 has claimed five major titles in a row; again Williams will match that with success in New York.
However, although she has won the three majors this year, not all matches have been straightforward.
She beat Maria Sharapova in straight sets in the Australian Open but it was a hard match, the Russian having several chances to seize the initiative.
At Roland Garros, Czech star Lucie Safarova, in her first Grand Slam final, won the second set on a tie-break and broke for a 2-0 lead in the decider only for Williams to recover and win through.
At Wimbledon she was involved in one of the matches of the tournament when beating Heather Watson, after the British number one had served for the match at 5-4 in the third set.
Also, in the final, she was given a scare by Garbine Muguruza, another final debutant, who ran her close in both sets.
Simona Halep is the world number two and met Williams in the final of their most recent tournament, the Cincinnati Masters, with Williams winning in straight sets.
The American has a 6-1 winning record against Halep who has two titles to her name so far this year; the Dubai Championships and the Indian Wells Masters.
However, her Grand Slam record in 2015 is indifferent, reaching the quarter-finals in Melbourne but losing early at the French Open and Wimbledon.
She will be looking for a good tournament in New York to sustain her position behind Williams at the top of the women's game.
Maria Sharapova has won the US Open once before, in 2006, and will hope to avoid meeting Williams this year.
The last time she beat the American was back in 2004, with over a decade of Williams dominance in which she has beaten Sharapova 17 times in a row including twice this year - the final of the Australian Open and the semi-final at Wimbledon.
Caroline Wozniacki is fourth in the world rankings and reached the final in New York last year, losing out to Williams in straight sets. Both her Grand Slam final appearances have come at Flushing Meadows.
Petra Kvitova is a two-time Grand Slam winner but both of those successes have come at Wimbledon and she has struggled to show the same form at the other Slams, especially in New York where she has never gone beyond the fourth round.
Others in the top 10 hoping for a good US Open include Safarova and Muguruza, hoping to add to those maiden Grand Slam final appearances, and Ana Ivanovic, making a welcome return to the top of the women's game.
She has a 1-9 record against Williams but troubled her in their most recent meeting in Cincinnati, leading by a set and a break.
However, her record at the US Open is modest, with a sole quarter-final appearance in 2012.
Most eyes will be on Williams in the coming days but if she fails, there are a host of players waiting to take advantage.