Christiaan Bezuidenhout saw his lead cut to three shots by local favourite Jon Rahm as the Estrella Damm N.A. Andalucía Masters hosted by the Sergio Garcia Foundation got set for a dramatic conclusion at Real Club Valderrama.
The South African started the day five ahead and extended that lead to seven in the early stages but four bogeys in five holes saw him turn in 36 at nine under.
Rahm played his first nine holes in 34 to get to six under, two ahead of fellow Spaniards Garcia, Eduardo de la Riva and Alvaro Quiros, Frenchman Mike Lorenzo-Vera and Japan's Hideto Tanihara.
The top three players in the top ten not already exempt will earn a place at The Open Championship and Bezuidenhout, Lorenzo-Vera and Quiros were on course for an appearance at Royal Portrush.
Bezuidenhout made a flying start with approaches to ten and four feet at the first and second to get to 12 under.
Rahm had also birdied the first from five feet but when he hit a poor tee shot on the second and then missed the green, the lead was up to seven.
Bezuidenhout found a nasty lie at the third for a first bogey of the day and a Tanihara birdie thanks to a long putt at the fifth reduced the gap to five.
Rahm holed an 18 footer on the fourth to also sit five back and while Bezuidenhout missed the green to surrender a shot at the fifth, the lead stayed at five as Rahm failed to get up and down from a plugged lie in a bunker.
Tanihara dropped shots on the fifth and ninth to leave Rahm in solo second and Bezuidenhout began moving back towards the home favourite.
The 25-year-old had scrambled brilliantly in round three but his magic touch appeared to have left him as he failed to get up and down from a bunker at the sixth and then dropped another shot on the seventh after coming up short of the green.
A two shot swing looked on the cards when Bezuidenhout found more sand on the eighth but this time he did save par as Rahm saw his birdie putt from the fringe agonisingly lip out.
That may have just been the fillip Bezuidenhout needed and he hit a wonderful approach to eight feet on the ninth and rolled in a left to righter for birdie.
The lead stayed at three, however, as playing partner Rahm produced possibly the birdie of the week, getting inside Bezuidenhout after hitting a remarkable second from the trees.
Quiros produced another roller coaster of a round as he made eight birdies and three bogeys to finish his week with a 66.
Garcia had birdies on the seventh and 11th in his opening 13 holes, Lorenzo-Vera was three under through 16 and De la Riva was two under having completed 11.
