4. Hao-Ching Chan and Yung-Jan Chan
They are two of the absolute best players from China. Between the two, the older one Yung-Jan Chan has been winning doubles titles right since the beginning of her career. At the age of 15, she won the Australian Open Junior doubles title.
The younger sister Hao-Ching has performed remarkably on the WTA tour too. This year during the Western and Southern Open they won their 4th WTA title together.
The Chan sisters are both ranked number 6 in doubles.
5. Serena Williams and Venus Williams
Venus and Serena Williams are fierce rivals and absolute powerhouses when it comes to the game. They won numerous singles titles separately, and also a slew of doubles titles together.
The two siblings have also won two gold medals at the Olympics for the US. They were coached by their parents Richard Williams and Oracene since an early age.
Venus Williams and Father Richard recall one match that 7-time Grand Slam champion "should have won"