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.
