<p>The 19-year-old Canadian teamed up with Williams to win a ‌doubles match on Tuesday as ⁠the ‌44-year-old American great returned to action after ​almost four years away from the sport.</p><p>Having beaten ​third seeds Nicole Melichar-Martinez and Erin Routliffe they were scheduled to ⁠face Leylah ​Fernandez and Laura Siegemund in the quarter-finals on Thursday.</p><p>Mboko, trailing 6-2, 3-4 to the powerful Czech ‌player, had a break point but fell awkwardly on the slick grass behind the baseline as she tried to change direction.</p><p>After being helped to the net she looked uncomfortable and emotional and opted to retire.</p><p>Earlier on ‌a showery day at the ​pre-Wimbledon tournament, second seed Amanda Anisimova ‌breezed past Germany's Laura Siegemund 6-1, 6-3 to set up a quarter-final against fellow American Iva Jovic who easily ⁠beat Alexandra ⁠Eala 6-2, 6-2.</p>