UPDATE 1-Tennis-Open-Murray thrashes Chela to reach second round

* Murray impresses in Chela demolition

* Says he surprised himself with the performance

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PARIS, May 24 (Reuters) - World number three Andy Murray started his French Open campaign with a 6-2 6-2 6-1 demolition of Argentine Juan Ignacio Chela to book a second round ticket on Sunday.

The Briton, chasing his first grand slam title, will next face either Germany's Mischa Zverev or Italian Potito Starace.

"I wasn't expecting to play that well on the first match. I hit a lot of winners," Murray, who has never won a title on clay, told reporters.

"I dictated most of the points and when the rallies went long, which he normally likes, I was coming up on top a lot. If I played that well in all my matches, I've got a good chance of winning comfortably.

"But I wasn't expecting to play that well, and it was a bit surprising."