But it seemed Venus was more tired that Serena. She put many volleys into the net and struggled getting her first serve in.
Venus and Serena only play doubles at Grand Slam events and the Olympics and therefore are usually unseeded, yet they've won 13 major titles and three Olympic gold medals together. Venus, 33, has already said she'd like a chance at a fourth doubles gold in 2016 in Brazil.
Hlavackova and Hradeckva will meet Australians Ashleigh Barty and Casey Dellacqua, seeded eighth, in the women's doubles final Saturday.