With the two sides deadlocked at the end of ordinary time the fact that both sides had each scored a try meant it came down to the type of kicks landed and Wales' penalty edged them through ahead of the young Springboks' drop goal.
Wales will now meet New Zealand at Stradey Park on Sunday thanks to stand- off Ceri Sweeney coming good when it mattered. In the final minute he saw a penalty goal attempt bounce back off the left up-right but maintained his composure when presented with another chance after three minutes of injury time to send the 8,000-strong crowd swarming on to the pitch.
A game of attack and counter-attack was illuminated by the dazzling performance of the Wales full-back, Rhys Williams. He repeatedly tore into the South African defence and thoroughly deserved to finish on the winning side.
South Africa took the lead with a try by wing Martin Holland, converted by the stand-off Tiaan Snyman.
Wales responded with an enthralling try of their own when Williams cut through and Sweeney was alongside in support to go over with the No 10 adding the conversion himself. The South Africans went back in front with a Snyman drop goal only for Wales to snatch the game in the final moments.
Sweeney had not had the best of nights with his kicking and there was silence as he lined up what was clearly going to be Wales' last chance. The captain, Adam Jones, and his pack had done everything they could in meeting the bigger South Africans head on, with the back row forwards Michael Owen and James Bater outstanding. Sweeney, however, was undaunted and his successful penalty kick means Wales now meet the junior All Blacks in what should be a marvellous finale to the tournament.
New Zealand, competing in the championship for the first time, ran out 21-15 winners over Ireland in the earlier semi-final. The Irish, hoping to retain the title, were never really in a position to overcome the side from the southern hemisphere and had to be content with five penalty goals from their stand-off, Jeremy Staunton.
The well-drilled Kiwis were always in command, with their pace from deep positions presenting the Irish with all manner of problems. Gerrard Fasaualu scored their first two tries with Shannon Paku claiming a third in the second half.
Ireland showed tremendous spirit but it was not enough.Reuse content