Serena Williams and Victoria Azarenka stormed into the final of the US Open with crushing victories in Friday’s semis to set up a classic showdown between the greatest player of her generation and the current world number one. Williams was at her ruthless best as she demolished Italian Sara Errani 6-1 6-2 to continue her golden summer while Azarenka was no less impressive as she clawed her way out of trouble to beat Maria Sharapova 3-6 6-2 6-4 at Flushing Meadows.