John Parry mounted a major offensive on Castle Stuart yesterday and surged to the head of the field during the first round of the Aberdeen Asset Management Scottish Open.

In the inviting, calm conditions which eventually led to 117 players, out of a starting line-up of 156, breaking par, the Englishman set the standard with a fine eight-under 64 to finish a stroke clear of countryman Simon Khan. Phil Mickelson, the four-time major champion, lurks in third on 66 sharing that spot with a posse that also includes Scotsman Chris Doak.

Parry, the former Walker Cup player who won on the European Tour in 2010, has struggled to find his form this season after regaining his playing rights at the qualifying school. The 26-year-old from Harrogate earned a place in last month's US Open at Merion and, having finished in a tie for 28th there on his major debut, the former Spanish Amateur champion believes that can help turn his fortunes around.

Parry, who launched his assault with back-to-back birdies on his first two holes, said: "I think the US Open was the catalyst for me playing better and making cuts. It's an event renowned for being the toughest of the year and you know that if you can compete in that, then you can compete anywhere. It's been good for the confidence."

Parry lost his full card at the end of the 2012 season but believes he has learned some important lessons ahead of another battle to safeguard his status at the top table. He added: "I think last year I maybe panicked a bit coming into the last few events of the year because I knew I was struggling. Now I know what it's about and I'm just trying to make sure I constantly do all the right things."

Mickelson, the world No.8, bounced back from a bogey on his opening hole to post a six-under 66 but admitted he should have been even lower. "I'll certainly take 66," he said, "but there was a chance today to go really low. There were opportunities to pick up maybe four or five shots that I let go and I've just go to get a little sharper."