Japan's Kei Nishikori lost his opening match of the clay season on Wednesday, with Asia's top player crashing to a 7-5, 6-4 defeat to Pierre-Hugues Herbert at the Monte Carlo Masters.

Fifth seed Nishikori reached the final here last year but will lose a chunk of ranking points after he hit 25 unforced errors and just 14 winners in succumbing to Frenchman Herbert. Nishikori will now move on to Barcelona next week, where he owns two titles as he works on his clay form as the run-up to Roland Garros intensifies. Herbert, who overcame Fernando Verdasco in the first roud, struck 31 winners in his upset to avenge a three-set loss to Nishikori in Rotterdam earlier this season.