Stanislas Wawrinka returned to form with a 6-1, 6-1 thrashing of Tomas Berdych at the ATP World Tour Finals on Monday.
The Australian Open champion has endured a dismal run of results since the US Open, winning only one Tour match since then, but the Swiss looked back to his best as he opened proceedings in Group A at the O2 Arena.
He came within a point of winning the opening set 6-0 but was thwarted by a Berdych ace.
His opponent could not turn the tide, however, and last year's semi-finalist Wawrinka wrapped up victory in 58 minutes.
Later on Monday, world number one Novak Djokovic begins his quest for a third consecutive title in London when he takes on US Open champion Marin Cilic.
In early doubles play, third seeds Alexander Peya (Austria) and Bruno Soares (Brazil) edged out Jean-Julien Rojer (Netherlands) and Horia Tecau (Romania) in a deciding tiebreak.
