World number four Agnieszka Radwanska has withdrawn from the Cincinnati Open in order attend the funeral of her grandfather.

The 24-year-old Pole, who beat Elena Vesnina 6-0 6-2 to set up a quarter-final showdown with Li Na, said it was a difficult decision but insists that she needs to be with her family.

"I'm very sorry that I have to withdraw from the tournament," read a statement released by Radwanska. "Unfortunately, my granddad passed away last Sunday. The funeral is going to be Saturday and I need to be there.

"I am disappointed to not continue with the tournament, especially because of my form so far this week. It was a difficult decision, but I need to be go home and be with my family."

Li will face either Serena Williams or Simona Halep for a place in the final.