The 30-year-old, who won the Scottish Open the last time it was staged at Gullane in 2015, went out in five-under-par 30 – including an eagle at the downhill 398-yard par-4 sixth.

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Birdies at the 11th and 12th holes saw Fowler move to seven-under-par for his round and, with Gullane a par-70, it raised the possibility of a first round of 59 on the European Tour, with Fowler needing to birdie four of his last six holes.

Fowler's five rounds at Gullane:

66, 68, 66, 68, 64#ASIScottishOpenpic.twitter.com/acngxWzPLk

— The European Tour (@EuropeanTour) July 12, 2018

However, the American faltered with a bogey on the par-4 13th and then parred his way in.

"After yesterday and seeing the golf course in the same wind that we're seeing today, I knew it was out there to get a few in the first six to nine holes and, at the same time, you've still got to hit fairways, hit greens and make putts," said the American.

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"It was nice to go out and execute early and would have been nice to get a few more on the back. The back was playing tougher coming in and could have presented some trouble but I feel like we did a good job of avoiding that."

Joining Fowler at the summit was Robert Rock - who birdied six of his first 12 holes before parring his way in - Scott Fernandez and Jens Dantorp.