David McNamee enjoyed a sensational debut following his move up to Ironman triathlon after coming seventh in yesterday's African championships in South Africa.

The 27-year-old from Irvine, who had never run a full marathon before the event, emerged in the leading pack from the swim in Port Elizabeth to put himself in the frame for a shock podium finish.

And although McNamee - also seventh at last year's Commonwealth Games - lost ground on the bike, a storming run saw him cross the line in 8 hours, 43 minutes and 35 seconds, with Belgium's Frederik van Lierde winning in 8:16 and fellow Scot Fraser Cartmell 19th in 9:07:13.

Meanwhile Grant Sheldon has admitted he may need to go back to the drawing board after quitting before the half-way mark at the ITU World Series in Auckland yesterday.

With Great Britain team-mate Jonny Brownlee pulling clear of world champion Javier Gomez to take victory in 1:55:26, the 21-year-old Glaswegian delivered a stark verdict on his efforts which lasted only to the initial section of the bike stage.

"The first lap of the swim was good but I started to drift back," Sheldon said. "Then I got dropped from the chase pack on the first hill - something I would usually consider a strength. I had nothing to give after that.

"After getting dropped from a few more packs, I dropped out. I lost a lot of pride in myself by doing that. I need to re-evaluate and decide where to go from here."

Gwen Jorgensen of the USA won the women's race in 2:09:04.