'Reward' for Williams sisters

The success of American women at this year's US Open is nothing less than a reward for the Williams sisters' inspiration to the younger generation, according to former world No 1 Mats Wilander.

Venus Williams, Sloane Stephens, Madison Keys and CoCo Vandeweghe all qualified for the semifinals, virtually guaranteeing that all 23,771 seats in Arthur Ashe Stadium will be occupied on Thursday and again for Saturday's final.

Serena Williams missed the tournament as she was expecting her first child.