Jordan Spieth saw his three-stroke overnight advantage at The Open wiped out inside four holes of the final round as a shocking start enabled Matt Kuchar to tie the lead at Royal Birkdale.
There appeared to be only two realistic contenders for the Claret Jug when Sunday began, with the last pairing well clear of the rest of the field.
However, Spieth duly bogeyed the first, third and fourth to slip back to eight under for the tournament, with Kuchar on the same score after completing his first four in level par.
Spieth's abysmal start, which featured two short missed putts, brought back memories of his final-round collapse at Augusta in 2016, although the 23-year-old Texan nevertheless remained in an excellent position to claim victory.
Spieth three-putts again and his lead has vanished! He and Kuchar, who parred from the sand, walk off the 4th at -8 https://t.co/ZBw1iLvFn2-- The Open (@TheOpen) July 23, 2017
The world number three bogeyed the first hole after finding a troublesome lie in thick rough to the left of the fairway and his lead was down to a solitary stroke when Kuchar fired a wonderful approach to the second to leave a tap-in birdie.
Things got worse for Spieth when he missed a short par putt on the third after going over the back of the green in two.
Kuchar also bogeyed the hole, meaning his playing partner continued to hold sole possession of the lead at nine under. Yet Spieth then three-putted from distance at the fourth, as Kuchar got up and down from sand to save par.
Li Haotong carded a superb 63 - completed with four birdies in succession - to vault up to third at six under, with Brooks Koepka, Branden Grace and Alex Noren all two shots further back and four behind Spieth.
The R&A confirmed on Sunday that this year's Open had attracted the third-highest crowd in the tournament's history, with 235,000 spectators attending. That total represented an increase of 17 per cent compared to when Birkdale last hosted The Open in 2008. Only St Andrews has played host to a larger crowd for the championship.