Gunning for her maiden US Open title, unseeded Victoria Azarenka came from behind to upset 23-time Grand Slam champion Serena Williams and booked a final berth on Friday. It is the first Grand Slam final for the former World number 1 in 7 years. After going down 1-6 in the first set, the 31-year-old bounced back to take the next two 6-3, 6-3. With her first-ever victory over Serena at the US Open, Azarenka took her winning streak to 11 matches. She will now take on Japan's Naomi Osaka in the final showdown on Sunday.