Kazakhstan's Elena Rybakina advanced to the National Bank Open semifinals after Ukraine's Marta Kostyuk was forced to retire with an apparent arm injury while trailing 6-1, 2-1 in women's singles action Monday in Montreal.

The Canadian advanced to the semifinals of the National Bank Open presented by Rogers with a 6-4, 6-2 win over Spain's Jessica Bouzas Maneiro on Monday in Montreal. Monday's triumph comes just two days after Mboko picked up the biggest win of her career by upsetting No. 1-seeded Coco Gauff in straight sets on Saturday.

Marta Kostyuk of Ukraine and Elena Rybakina of Kazakhstan have advanced to the quarterfinals of the women's National Bank Open in Montreal.