The Sharks made themselves odds on for a home semi when beating the Hurricanes 33-17 in Durban to stay on top.
They lead Chiefs, who pipped Auto & General Lions 36-29 in Hamilton.
Lions took a 22-10 half-time lead but allowed Chiefs to score 26 unanswered points in the final 20 minutes - Lions' are on 12th spot in the table.
The Bulls suffered their second consecutive loss 13-16 to the Crusaders in Christchurch on Friday to remain in fourth with a game in hand. The Stormers were disappointing in going down 6-12 against the Waratahs in Sydney on Saturday.
Also the Cheetahs' first home match ended in disappointment as they lost 40-27 to the Brumbies.
And the Western Force gave themselves hope thrashing the Reds 39-7 in Perth on Friday to move up into tenth place.
This weekend also saw Springbok centre Jaque Fourie becoming the second leading try scorer in the 2009 tournament. - Sapa