American Ally Ewing stormed into a five-shot lead with a brilliant second-round 66 in the Women's British Open at Walton Heath on Friday.

The 30-year-old led by one stroke after an opening 68 and a seven-birdie round put her on 10 under par and in control after the early starters had completed their second rounds at the last major of the year.

Ewing had a magical run of four birdies in a row from the sixth and her only mistake came at the tough closing hole where she drove into the rough and took a bogey five.

"I was definitely in the zone when I had that string of birdies," said Ewing. “But I just tried to stay in the here and now.

"It would be huge to become a major champion, it's definitely something I've circled to accomplish in my career. But now I need a good rest and get ready for tomorrow."

Lilia Vu, winner of the first major of the season at the Chevron Championship, enhanced her hopes with a second-round 68 to reach four under and US Women's Open champion Allisen Corpuz was one further back after a 71.

American Andrea Lee (68) and Japan's Minami Katsu (69) were Ewing's closest challengers in a share of second spot on five under par.

But defending champion Ashleigh Buhai shot 73 for a three-over total and was likely to miss the cut.

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