The World Cup quarter-final between Australia and South Africa will hinge on the breakdown, with \"jackals\" Heinrich Brussow and David Pocock to play key roles, Boks assistant coach Gary Gold said Friday. Gold said conditions in Wellington for Sunday\'s clash were likely to be soggy after almost a week of rain, making the ball scavenging skills of South Africa openside flanker Brussow and his Wallaby counterpart Pocock crucial. \"The breakdown will probably be the defining factor at the weekend, both on attack and defence,\" Gold said. \"The teams that master the breakdown this weekend and adhere to the referee\'s interpretations the best, are going to be in the best position to win.\" Gold said that meant Brussow and Pocock, both regarded as among the world\'s top openside flankers, could turn the game. \"There are two significant forces this weekend and both teams are going to have to be on their toes when those two jackals come close to the breakdown,\" he said. Gold believed the Australian scrum had recovered from a poor performance against Ireland, which resulted in a famous 15-6 victory for the Irish, and would be confident facing South Africa after two wins over the Springboks this year. \"Australian teams can live with the best physical teams in the world at the moment,\" he said. \"I\'m not sure that was necessarily the case four or five years ago, with regards to the Australian pack . \"They\'ve got youth and athleticism -- so they\'ve exciting backs moving them around the park and forwards who can keep up with them. They\'re a dangerous team.\" Gold said the reigning champions were desperate to build on the success that had brought South Africa two world titles. \"I\'ve heard how important is is for New Zealand but it\'s equally important for us,\" he said. \"We\'ve seen how success in the big stage like this for our sports teams have got a very strong way of uniting our country. \"It\'s important for us and we realise the responsibility, that responsibility is heavy on the shoulders of the guys -- not as a burden but in a way that they want to meet the challenge. \"Also, there\'s guys obviously playing their last World Cup and they want to go out on a high and leave a legacy.\"