Top seed champion Stan Wawrinka of Switzerland muscled into the second round of the Japan Open on Tuesday with a bludgeoning 7-5, 6-3 victory over Radek Stepanek of the Czech Republic.

French Open champion Wawrinka produced a dazzling performance in the Tokyo sunshine, unleashing a series of jaw-dropping backhands that left his opponent shaking his head in disbelief.

"After last year I'm just happy to play well and get through the match," said Wawrinka, who was eliminated by Japan's Tatsuma Ito in the first round last year in a stunning upset and faces the same player in his next match.