[2] American John Isner and doubles partners Vasek Pospisil and Jack Sock headlined the event as the top three seeds.
Isner, a two-time defending champion, advanced to the third straight final, losing only one set against fellow American and a qualifier at the tournament Denis Kudla in semifinals.
In the other side of the draw, Angelique Kerber defeated Radwańska in three sets, before easy semifinal win over eight seed Elina Svitolina.
Eight of the world top 10 players headlined the event, with Novak Djokovic, Andy Murray and Stan Wawrinka led the field.
Though Williams came fresh-off two grand slam titles, it was all about young Swiss Belinda Bencic in that half of draw, who defeated five Grand Slam finalists in a row to reach the final, including also three wins over top 10 players at the moment, against Caroline Wozniacki, Ana Ivanovic in quarterfinals, and Williams in semifinals.
In the bottom half of the draw, Halep faced also three grand slam finalists, and after defeating Sara Errani she reached the final.
In the final, Bencic became the youngest player to win the tournament, overtaking feat from Ivanovic, when was up 7–6(7–5), 6–7(4–7), 3–0 before another grand slam finalist Halep retired.