Camila Giorgi
This 25-year-old Italian tennis player shocked the world when she defeated Caroline Wozniacki, Maria Sharapova, and Victoria Azarenka, who were all number one tennis stars. Interestingly enough, she has won more games against top 10 players than she has lost. Despite her small size, she has also managed to surprise us with her strong serves, like her best of 116 mph (186 km/h).
Elina Svitolina
Okay, granted she may not have the fastest serve of all time (98 mph (108 km/h)), but she definitely needs to be mentioned. The young 23-year-old Ukrainian has already taken home more than $7 million worth of prize money and has climbed to 7th position on the world charts.