The Lions ground out a 27-10 Super Rugby final-round victory in Durban over the Sharks on Saturday to top the overall standings, which guarantees home advantage in every knockout match they play.
The teams clash again next weekend in the quarter-finals of the annual southern hemisphere championship with the Johannesburg-based Lions playing in front of their supporters.
A try by fullback Andries Coetzee after the hooter sounded for half-time gave the visitors a 13-10 advantage at the break at Kings Park.
The Lions kept Sharks scoreless in the second half of a scrappy match while adding 14 points from a try and three penalties to make it 14 wins in 15 regular-season matches.
They finished with 65 points, two more than long-time leaders Canterbury Crusaders, who fell 31-22 at Wellington Hurricanes earlier Saturday in a New Zealand derby.
Try: van Wyk
Tries: Marx, Coetzee, Kriel
Pens: Jantjies 4
Bulls v Stormers
Sevens star Seabelo Senatla scored with 73 seconds left to seal a 41-33 win for the Stormers over the Bulls on Saturday in Pretoria in a lively Super Rugby "dead rubber".
Stormers scored six tries and Bulls five to entertain the crowd at Loftus Versfeld stadium in a final round league match where only pride was at stake.
Cape Town-based Stormers had already won the Africa 1 conference and secured a home quarter-final against tw0-time champions the Chiefs.
Outgoing Bulls coach Nollis Marais would have loved to finish a dismal season with a win, but it was not to be as New Zealander John Mitchell takes charge next season.
Tries: Jenkins, Matthews, Kriel 2, van Zyl
Cons: Schoeman 3, Jantjies
Tries: Kolbe, Notshe, Leyds, Kolisi, Willemse, Senatla
Cons: Willemse 4
Yellow card: Bulls: Conraad van Vuuren (52 minutes)
Sunwolves 48 Blues 21
Force 40 Waratahs 11
Chiefs 28 Brumbies 10
Hurricanes 31 Crusaders 22
Southern Kings 20 Cheetahs 21
Melbourne Rebels 29 Jaguares 32
Highlanders 40 Queensland Reds 17