The Neangar Park golfer fired a bogey-free eight-under par 63 to grab a one-shot lead over European Tour event winners Matt Wallace, Shane Lowry and Eddie Pepperell.

Chinese star Li Haotong (-6) and US Masters champion Sergio Garcia (-5) are lurking not far behind.

With only three events remaining after the Portugal Masters, a top-10 finish this week would all but guarantee Herbert a place inside the top 110 on the Race to Dubai rankings and an automatic European Tour card for 2019.

“There's a lot of pressure coming into this time of the year,” Herbert told europeantour.com.

“Most of the other guys will probably get more starts than me to finish off the year so there's probably a bit of pressure on me to play well.

“I think I've had that pressure all year and I've dealt with it pretty well. Obviously today was a good indication that it's going alright so hopefully I can just continue that form.

“I've probably not played that great and still kept some consistent form, I think that's the biggest takeaway. I've actually played some good golf today and reaped the benefits.”

Herbert, who played the back nine first in his opening round, made a blisering start with four birdies and an eagle in his opening nine holes.

Birdies on the third and sixth holes saw him jump to the top of the leaderboard.