Cameron Smith has fought back tears describing his worst day as a pro golfer, the local favourite shooting a seven-over 78 to miss the cut in his Australian PGA Championship defence.

While Min Woo Lee and Adam Scott are primed for a title shootout, the three-time event champion Smith will have the weekend off to ponder what went wrong in Brisbane.

The three-time champion started 10 shots off the lead on Friday at Royal Queensland but slid further behind.

A double bogey at 10 and bogeys on the final two holes lowered him to nine over for the tournament, well behind the projected cut line of one under and 21 shots behind leader Lee (12 under) in equal 148th place.

The former world No.2 said he couldn’t remember a worse day on the golf course as a pro.

“Yeah, no words. Shit,” Smith said while choking back tears. “I’ve performed under pressure before and it’s not acceptable, a bit upsetting actually.

“I know what I’m doing, it’s just going out there and committing to something is another thing.”

Smith missed putts, sprayed drives, found bunkers and again left irons short, the 2022 British Open champion shaking his head at what’s believed to be his worst round in tournament golf.

Good showings in Brisbane and at Sydney’s Australian Open next week were crucial for Smith, who as a LIV Golf member has limited chances to boost his ranking and earn selection for next year’s Paris Olympic Games.

Smith finished second in the LIV Golf season that concluded a month ago and was also runner-up in his only other appearance since, at this month’s Hong Kong Open.

“I hope I can get it together for next week and put on a better show than that,” he said, before spending the next 15 minutes signing autographs and posing for photos with fans.

Meanwhile, Lee (66) and Scott (65) traded birdies to move clear at 12 and 11 under respectively.

“It’s golf, that happens and next week I’m sure he’s going to bounce back, it’s what good players do,” Lee said of his out-of-sorts playing partner.

“With family and friends, in his hometown … a few drinks and loosen up for next week.”

A dialled-in Scott was unlucky not to have gone even lower after an eagle approach and hole-in-one effort on a par four both bobbled out.

John Lyras had a par on the 18th to card a round of 67 and back up his opening-day 65 to be outright third at 10 under, while an ace on the 17th party hole helped Curtis Luck (67) to eight under and a share for fourth with Lucas Herbert (68).

Lee matched his Thursday haul of four birdies on the front nine to claim an outright lead at 11 under before a bogey on the 10th.

Scott had an eagle putt on the seventh hole roll narrowly by and then an iron approach for eagle bounce out of the ninth cup.

But the 2013 Masters champion birdied both of those and made two more long birdie putts before a birdie on the 10th took him to 10 under and equal-first.

It continued on the 12th, Scott driving the 292m par four and watching as his ball skipped up the green, hit the flag and again bounced out.

Scott made birdie there to claim an outright lead for the first time, but Lee answered with clutch putts down the stretch to edge ahead again.

Earlier, Herbert revived his campaign with six birdies after quickly dropping three shots to finish eight under.

Cameron John carded a six-under 65 to be seven under, while overnight leader Joel Moscatel Naschshon of Spain dropped two shots to be six under through 11 holes.