The thought of the top men’s and women’s singles players teaming up is one that has often intrigued tennis fans around the world.

The U.S. Open overhauled its mixed doubles tournament in hopes of drawing the top singles players. The defending champions don’t intend to move out of the way so easily.

Veteran doubles experience overcame singles stardom as defending champions Andrea Vavassori and Sara Errani reached the semi-finals at the U.S. Open's reimagined mixed doubles on Tuesday, as the event kicked off with a new format and new fans.