The golfing world has reacted in shock after Lydia Ko's "all-time brutal meltdown" at the Marathon Classic on the LPGA Tour.

The Kiwi former world No 1 looked odds on to claim her first victory in 27 months after cruising out to a five-shot lead with six holes to play on the final round, having led the field over the first three days.

However, it all started to go downhill at the 14th when Ko bogied the par three, while world No 2 and last week's winner American Danielle Kang nailed two-straight birdies to close the gap to two shots.

After dropping one more shot at the par four 16th, Ko still had a one-stroke lead heading to the final hole.

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But on the par five 18th, Ko had a disaster: her second shot went onto the cart path, her third across the green and into the rough, and her fourth was the worst of them all, with a chip shot rolling back down the slope and into the bunker.

Once she was finally on the green, Kang had parred the hole, and Ko was left needing to hole a bogey putt merely to force a playoff. But she missed, and the double bogey saw her sign for a 73 and a share of second, and the best opportunity she's had in years to win a tournament disappear.

READ MORE: Lydia Ko's horror finish: How the dramatic final round unfolded

Golf pundits and fans across the world took to Twitter to share in Ko's heartbreak in one of the craziest and most brutal capitulations in golf.

Sports broadcaster Miles Davis said the finish was "like watching a car crash in slow motion".

Others shared in Ko's heartbreak: "I'm a huge Danielle Kang fan but my heart breaks for Lydia Ko, who had a comfortable lead for her first win in years and fell apart down the stretch and doubled the 72nd hole after a series of unforced errors. This one's going to hurt for a while."