Olympic champion Zheng Qinwen staged a stunning comeback to defeat Madison Keys, while Naomi Osaka survived a tough three-setter to reach the fourth round

The superstar sisters, whose 14 Grand Slam doubles titles include two US Opens, rallied from a break down in the third set and led the deciding 10-point tiebreaker 5-0 but fell 3-6, 7-6 (8/6), 6-7 (7/10).