Serena Williams saw off a significant threat to her Grand Slam hopes with victory over 19th seed Madison Keys at the US Open, and will now meet her sister, Venus in the quarter final.
Serena, the world number one, beat her fellow American 6-3 and 6-3 to set up a quarter-final against her sister Venus, who beat Estonia’s Annett Kontaveit 6-2 6-1. .
Serena, 33, is now three wins from competing the first calendar Grand Slam since Steffi Graf in 1988.
Novak Djokovic overcame an in-form Roberto Bautista Agut, subduing the Spanish 23rd seed 6-3 4-6 6-4 6-3.
The top seed, who has already won the Australian Open and Wimbledon this season, will face Bautista Agut’s compatriot Feliciano Lopez in the next round.
Men’s defending champion Marin Cilic and 19th seed Jo-Wilfried Tsonga both won and will meet in the last eight.