The veteran older sister of world number one Serena Williams won the WTA tournament in Wuhan last week , as Spain 's Garbine Muguruza retired during the final due to exhaustion .
Sister was already a set and three games down at that point .
The veteran older sister of world number one Serena Williams won the WTA tournament in Wuhan last week , as Spain 's Garbine Muguruza retired during the final due to exhaustion , although she was already a set and three games down at that point .