Serena Williams thrashes Svetlana Kuznetsova in Rome

Serena Williams is aiming for a fourth title at the Italian Open

World number one Serena Williams waltzed through to the Italian Open semi-finals by defeating ninth seed Svetlana Kuznetsova in straight sets.

The top seed, who ate dog food before her win over fellow American Christina McHale in the last round, beat Russian Kuznetsova 6-2 6-0 in 51 minutes.

Williams will now play Romania's Irina-Camelia Begu after she beat Japan's Misaki Doi 6-2-7-6.

In the other semi America's Madison Keys faces Spain's Garbine Muguruza.

Keys, 21, despatched Barbora Strycova of the Czech Republic 6-4 4-6 6-3, while 2015 Wimbledon finalist Muguruza beat Switzerland's Timea Bacsinszky 7-5 6-2.

Williams, who admitted being sick after eating dog food ordered off a menu for her Yorkshire Terrier, is aiming for a fourth Italian Open title.