Stanislas Wawrinka: 'Mental calmness helped me thrash Tomas Berdych'

Stanislas Wawrinka has admitted that his 'mental calmness' helped him to thrash Tomas Berdych at the ATP World Tour Finals.

The Australian Open champion got his campaign off to a winning start on Monday as he hammered Berdych 6-1 6-1 at the O2 Arena in London.

Wawrinka was dominant throughout against the Czech, dropping only two games in a match that lasted just one hour.

"For me, when I play against him it's always tough, but when I'm mentally calm I can always find a solution," the world number four is quoted as saying by BBC Sport. "I'm really happy with the way I handled the situation today."

Wawrinka has now won his last five matches in a row against Berdych.