Cape Town - Former All Black coach Laurie Mains has admitted that Ellis Park could be a tricky venue for the All Blacks when they tackle the Springboks in the Rugby Championship finale on Saturday.In order to win the competition, South Africa must beat New Zealand with a four-try bonus point and at the same time prevent the Kiwis from getting any bonus points themselves.That may be a tall order, but the 67-year-old Mains believes the ground is the best suited for the Boks to defeat the All Blacks.The All Blacks' last Test at the ground was a 40-26 loss in 2004 - and the New Zealanders have won only three of their 11 Tests at the ground since 1928. "South Africa in South Africa at any time are tough and at Ellis Park it will be tougher again," Mains told the stuff.co.nz website."Believe me, the Springboks are a better team than what we saw in Auckland (when the All Blacks won 29-15), where the referee destroyed the game and it largely counted against them. The All Blacks will do extremely well to win it."They should (win) with the dynamics of the team and the way they play. But it will be a very tough one." Mains - who was All Black coach when they lost the 1995 World Cup final to the Boks at Ellis Park - also said the high altitude could count against the Kiwis."It has always been difficult for visiting teams in that 15 minutes before half-time and in the last 20 minutes of a match," said Mains, who is familiar with the ground having also coached the former Cats franchise in 2000 and 2001.