Best of Australian Open - Day 8

Venus of the U.S. hits a return to Radwanska of Poland during their women's singles match at the Australian Open 2015 tennis tournament in Melbourne

Radwanska of Poland hits a return to Venus of the U.S. during their women's singles match at the Australian Open 2015 tennis tournament in Melbourne

Raonic of Canada hits a return to Lopez of Spain during their men's singles match at the Australian Open 2015 tennis tournament in Melbourne

Keys of the U.S. signs autographs after defeating compatriate Brengle in their women's singles match at the Australian Open 2015 tennis tournament in Melbourne

MELBOURNE, Australia (AP) -- The Williams sisters are back in the quarterfinals of a Grand Slam, and neither one is there just to watch.
— Associated Press