SERENA WILLIAMS exited the Western and Southern Open in Cincinnati today via a gruelling second-round defeat to Petra Kvitova.

The former world number one raced to victory in the opening round, but despite displaying some of her best tennis of late, she could not replicate the same form to advance to the last 16.

Number eight seed Kvitova applied the pressure from the start, breaking 23-time grand slam winner Williams twice in the first set.

Williams, who has won two titles in Cincinnati before, did not allow the momentum to drop in the second set, breaking her opponent in a marathon third game before grabbing a 5-2 lead and serving out for the set.

A nervy start to the third set saw both players drop their serve, but Kvitova found her stride to go 4-2 up and eventually emerge the 6-3 2-6 6-3 winner after two hours on court.

Meanwhile, number six seed Caroline Garcia fought back from 2-0 down in the first set and 5-3 in the second to overcome Victoria Azarenka 6-4 7-5 in one hour and 36 minutes.

Fifth seed Elina Svitolina faced an equally tough match against Svetlana Kuznetsova, with the Russian threatening Svitolina's lead in each set.

With the breaks going back and forth, the Ukrainian eventually held serve to seal a 7-6 (7/1) 4-6 6-4 victory.

Meanwhile, Britain’s Kyle Edmund suffered a straight-sets defeat to Denis Shapovalov in the second round.

Edmund, Britain’s last hope of the tournament, was defeated 6-4 7-5 by his 19-year-old Canadian opponent in one hour, 53 minutes.

Andy Murray was beaten 6-1 1-6 6-4 by Lucas Pouille in the first round on Tuesday, while Johanna Konta exited the tournament after being beaten 4-6 6-3 6-4 by Belarus’s Aryna Sabalenka.