Michael Hoey blamed a bloated stomach for a disappointing finish to his opening round at the Volvo Golf Champions.
The Northern Ireland golfer was on four under with three to play but blocked his drive at the 16th and then had another double-bogey on the 273-yard last after losing a ball in bushes.
Hoey came up with an unusual explanation for his bad finish.
“I felt so bloated,” said the former British amateur champion, winner last March of the Hassan Trophy in Morocco.
“I drank so much yesterday (when it was much hotter) and did the same, but I lost so much concentration. It was weird - I couldn’t swing it properly.”
Thailand’s Thongchai Jaidee defied strong winds to start the event with a brilliant seven-under-par 65 in Durban on Thursday.
Making his first ever trip to South Africa, the 43-year-old former paratrooper led by five at one point but then Dane Thomas Bjorn cut the gap to two by following an eagle at the long eighth with back-to-back birdies.
Hoey’s late collapse lifted Open champion Ernie Els, out in a three-under 33, into a tie for third with a group that included Scots Richie Ramsay and Scott Jamieson and England’s Danny Willett.
Jaidee, who qualified for the 33-strong winners-only field by capturing the Wales Open in wind and rain last June, said: “I’m very happy with that.
“I enjoy the course. You have to think a lot - I hit the driver on only two holes and I put a three-iron in my bag only 15 minutes before we teed off.”
Paul Lawrie and Colin Montgomerie, paired together, were two under and level par respectively, having been held up for 10 minutes on the first green. The flagstick was stuck in the hole and repair work was needed before they could continue.
Els, loser of a play-off to fellow South African Branden Grace at Fancourt last year, kicked off with three straight birdies, double-bogeyed the next, but as the expected rain arrived he picked up more shots on the seventh and ninth.
Darren Clarke was lying two over after 13 holes after recording three birdies, three bogeys and a double bogey in his round so far.
Irishmen Shane Lowry and Padraig Harrington are also part of the 33-man field in South Africa.