Oosthuizen, who was the leading world ranked player in the field, will move up two places to number 4 in the world ranking as a result of his come from behind victory.
Oosthuizen began the final round five shots adrift of Scotland's Jamieson but although both started well, Jamieson's double bogey at the 5th appeared to unsettle him and as he struggled to regroup Oosthuizen pushed forward with a series of birdies.
A bogey at the par four 16th opened the door for Jamieson but he too would bogey the same hole a few minutes later and although Jamieson birdied the final hole it was a case of too little too late.
For the 29 year old Jamieson however his visit to South Africa in recent weeks has been very productive. He won the Nelson Mandela event in December and then finished 3rd at the Alfred Dunhill before his runner-up finish this week. The former Augusta State University player now sits on top of the Race to Dubai money list and will move from 100 in the world ranking to an all time high of 70.
Thongchai Jaidee finished one shot behind Jamieson in 3rd position followed two shots further back by Padraig Harrington.
The European Tour now moves to Abu Dhabi for this week's Abu Dhabi HSBC Golf Championship where Rory McIlory and Tiger Wods compete followed by events in Qatar and Dubai before returning to South African for the Joburg and Africa Opens.