PRETORIA, SOUTH AFRICA - JUNE 18, during the Super Rugby match between Vodacom Bulls and the Sharks from Loftus Versfeld on June 18,0 2011 in Pretoria, South Africa Photo by Steve Haag / Gallo Images

Wellington - South Africa's Bulls will defend their week-old lead in the Super 15 in its southernmost stronghold when they take on the under-pressure Otago Highlanders in the weekend's 13th round.

The Pretoria-based Bulls took over first place last weekend when they scored a late try to beat the New South Wales Waratahs 27-24, their eighth win from 10 games, combined with the Waikato Chiefs' first loss in 10 matches.

Springbok super-boot Morne Steyn will play his 100th match for the Bulls, who will have to overcome injuries and one of the most hostile home grounds in the tournament at Dunedin, New Zealand, to maintain their place at the top of the table. - Sapa-AP