Herbert’s three-under 68 has him at nine-under through 54 holes, six shots back of co-leaders Xander Schauffele (68) and Collin Morikawa (67) as Northern Ireland’s Shane Lowry joined the fray by equalling the low majors mark with his round of nine-under 62.
Herbert likely needs something similar to join the list of genuine contenders for the Wanamaker Trophy yet the 28-year-old remains determined to fight for the best finish possible.
A tie for 13th at the PGA Championship two years ago is Herbert’s best result in a major to date and a maiden top-10 is among a handful of boxes he would like to tick at Valhalla Golf Club in Kentucky.
“There’s plenty to play for,” Herbert told the PGA of America.
“There’s a stack of exemptions based on wherever you finish so I’ve got that to think about.
“Even just getting to double digits under par in a major is pretty cool and something that not many people can say they’ve done.
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“If I was able to get to that score I think that would be a pretty good achievement.
“I’ve done a lot of work this year on my game so I’d love to play a nice, solid round tomorrow, at worst, and if we finish in the top-10 that would give me a lot of satisfaction for the hard work that I’ve put in.”
At nine-under-par Herbert is three shots clear of Jason Day (69) as the leading Aussie, Min Woo Lee (70) and Cameron Smith (70) both tied for 38th at five-under-par and 10 strokes off the lead.
Once round two was completed and a short suspension due to heavy fog was lifted, Herbert set about making an impression on the leaderboard.
He hit his approach shot from 196 yards at the second to 10 feet and made the putt for birdie and then backed that up with a 26-foot putt for birdie at the par-3 3rd.
He erased a dropped shot at six with a birdie at the par-5 7th, his final birdie of the day coming from 20 feet at the short par-4 13th.
Herbert received a free drop when his tee shot on 18 went left but made a par putt from nine feet to carry momentum into the final round.
“It’s nice to get off to a good start like that and obviously you want to continue it, but you do have to check yourself and make sure you don’t get too far ahead of yourself,” Herbert said of his bright start on Saturday.
“Off to a good start and, to be honest, I’m reasonably happy with the day. I probably left two shots out there – missed a short one on 10 and then made a bogey on six. Any time you can say you left two shots on the course you’ve had a pretty good day.
“I just need to iron out a couple of things to get ready for tomorrow and shouldn’t be too far away from things.”
Min Woo Lee is the first of the Aussies out at 12:55am AEST followed by Cameron Smith at 1:15am. Jason Day is paired with Zac Blair from 1:35am with Herbert to begin his final round at 3:15am alongside Belgian Thomas Detry.