Nino Bertasio opened with a bogey-free 61 to claim a four-shot lead after day one of the Portugal Masters.

The Italian finished his first round at the Dom Pedro Victoria Golf Course with eight pars and 10 birdies, including a six pack of gains over the last seven holes to reach 10-under par.

“I got off to a good start, birdied the second after hitting it close and I started making some putts,” said Bertasio, 33, who is seeking his first career victory.

“I wasn’t thinking about it [a 59], I’m not going to lie. Just trying to finish a good round. I wasn’t expecting a 61, but I have been playing nicely. I putted really well today and everything clicked.”

Spain’s Adri Arnaus was alone in second-place after carding a 6-under-par 65, while Malaysia’s Gavin Green (66) was one further back on 5 under.