PGA Tour pro makes octuple bogey (13!) on 16th hole at The American Express

PGA Tour rookie William Mouw made a tournament-ending octuple bogey 13 on the par-5 16th en route to an 81 in the second round of The American Express.

Mouw, 23, was moving along nicely at 2-under par thru 15 holes on the tougher Pete Dye Stadium Course of the three-rotatation courses used at The Amex.

He was also just outside the top 50 at the time on 6-under par and very much in contention to make his first PGA Tour cut of the season. 

But the wheels well and truly came off to Mouw after he sent his second shot into the famous giant bunker down the left flank of the 16th.

Mouw started the hole well, splitting the fairway with a 330-yard bomb down the heart of the fairway.

He was left with 275 yards from there but sent his fairway wood into the one place you just can't go on 16, left into the sand. 

What happened thereafter will likely haunt Mouw for the rest of his PGA Tour career as he proceeded to make a Baker's Dozen.

Mouw splashed out his ball out of the bunker but it sailed over the back of the green into a horrid lie in the rough. 

He pitched his ball back on to the green but his ball caught the downslope and travelled back into the sand. 

The World No.169 needed two attempts this time to get his ball out of the sand.

He eventually got his seventh shot out of the sand but once again ended up in the back rough. 

Mouw then did exactly what he did last time around by chipping his eighth shot back into the bunker.

The former Pepperdine player elected to play to the right fairway from there with his ninth shot. 

But then he still managed to pitch his 10th shot from there over the back of the green.

He finally found the green with his 11th shot, chipping up to 65 feet and he would two-putt from there for a shocking octuple-bogey 13. 

Understandably rocked by what had just unfolded over the past five minutes, Mouw went on to make a triple-bogey six on the island green par-3 17th after twice finding the water from the tee. 

To Mouw's credit, he holed a 30-footer for a six. 

He went on to par the par-4 18th but it all added up to a 9-over 81, leaving Mouw at 5-over par for the tournament in 152nd and well outside the cut mark.

The American Express is a 72-hole event played over three different courses over the first three rounds - Stadium Course, Nicklaus Tournament Course, La Quinta. The final round is then played on the Stadium Course. 

Watch Mouw's meltdown on 16 here:

At the top of the board, Charley Hoffman and Rico Hoey lead the way after 36 holes at 16-under par. 

Justin Lower, Sepp Straka and Mark Hubbard are one shot back on 15-under par.

Former World No.1 Jason Day is a further shot back alongside in-form JJ Spaun.

Pre-tournament favourite Justin Thomas is on 13-under par alongside last week's winner NIck Taylor and Rickie Fowler.

Keep up to date with live scores here.

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