Elena Rybakina crashed out of the China Open with a shock second-round defeat to unseeded Alina Charaeva, marking a disappointing start to her reign as World No 1.
The 27-year-old was playing for the first time since defeating four-times major winner Aryna Sabalenka to capture the US Open title last month, which saw her leapfrog the Belarusian into top spot in the world rankings.