The South African started round four with a five-shot lead and it was still three strokes after the front nine, but disaster struck on the 15th hole when she made a triple-bogey seven.

Buhai finished her round four over par and 10 under the the tournament on the Scottish links course, tied with Chun.

The South Korean's one-under 70 was enough for a share of the 72-hole lead.

Buhai and Chun played the 18th hole four additional times before there was finally something to separate them.  

Whereas Chun drove into a bunker, chipped out and then played an impressive third shot to be in with a chance of salvaging par, Buhai followed up a stellar drive by finding a greenside bunker.

However, a brilliant chip out and Chun's par putt coming up short meant Buhai had a two-foot putt to seal a first major victory.

The 33-year-old buried the putt and then buried her face in her hat, overcome with relief.

Buhai only had one top-five finish at a major before this week.

Chun, by contrast, won her third career major earlier this year.

Japan's 2019 champion Hinako Shibuno hit an even-par 71 and missed the playoff by a lone shot.

Ireland's Leona Maguire was five under par for the final round and seven under for the tournament, sharing fourth place with Minjee Lee of Australia and Swede Madelene Sagström.