The last five women’s Grand Slams have been won by different players, while the likes of Simona Halep and Eugenie Bouchard look on the cusp of taking one of tennis’ big four for the first time.
Below are five players that remain largely under the radar, yet have the capabilities of springing some surprises at the US Open.
Having reached the final of the Australian Open when dumping out top-five ranked Maria Sharapova and Agnieszka Radwanska along the way, Cibulkova reaped the rewards of being ultra aggressive.
Punters can expect a similar level of attack in the US.
Makarova is fairly consistent on all surfaces, reaching at least the third round of seven of the last eight Grand Slams, and has avoided going out in the first round at any of her last 11 hard-court events.
A quarter-finalist at the US Open last year before losing in three sets to Na Li.
The Italian has reached at least the quarter finals in four of her last five US Open appearances and made the same round of the Australian Open this year.
She has also already won a hard-court tournament this season when beating the likes of Sam Stosur, Sloane Stephens, Na Li and Radwanska to lift the trophy at Indian Wells.
In her home Grand Slam last year, Riske knocked out Wimbledon champion Petra Kvitova en route to the fourth round, while in Australia this term she dropped just six games across the opening two rounds, before losing to Angelique Kerber.
The Croatian teenager was victorious in her last hard-court tournament by beating Cibulkova in the final and also went well in Miami until running into Kvitova.
Vekic has been pretty indifferent since, but the harder courts do seem to be her preferred surface.