The Sharks picked up just their fourth win in style by hammering the Highlanders 38-12 and hurting the New Zealand side's Super Rugby title chase on Saturday.
The Sharks scored five tries to the Highlanders' two, starting when hooker Armand van der Merwe went over in the first minute.
The defeat lost the Highlanders ground in the New Zealand conference, where leaders the Crusaders and the second-placed Hurricanes both won.
The defending champion Crusaders were the biggest winners of the round as their nearest chasers in the overall standings, the Lions of South Africa and Waratahs of Australia, also lost.
The most serious challenge to the Christchurch-based Crusaders appears now to be from the Hurricanes, who are just two points behind and have played a game less. The Wellington-based Hurricanes saw off the Lions 28-19.
As conference leaders, the Crusaders, Lions and Waratahs occupy the top three places. New Zealand trio the Hurricanes, Highlanders and Chiefs, surprise package the Jaguares of Argentina, and the Sharks of South Africa complete the playoff places.
Van der Merwe's try was the first of two for the Sharks in the opening seven minutes in Durban as wing Makazole Mapimpi also scored.
Flanker Dillon Hunt hit back for the Highlanders for 14-7 but that was the closest the visitors got as they struggled to get their expansive game going on a heavy field.
The Sharks played off their supremacy up front and at the breakdown to add tries by No. 8 Dan du Preez, wing Sibusiso Nkosi and flyhalf Robert du Preez in the second half, clinching a bonus point despite center Teihorangi Walden's late try for the Highlanders, created brilliantly by All Blacks fullback Ben Smith.
That bonus point was key for the Sharks as it took them to eighth overall and into the final wild card place at the expense of the Stormers.
The Cape Town-based Stormers earlier overpowered the Pretoria-based Bulls 29-17 in their north-south South African derby, also the 100th Super Rugby appearance for Stormers captain Siya Kolisi.
In a game centered on the battle between two bruising sets of forwards, the Stormers pushed 12-0 ahead in the first 11 minutes, prompting a response from the Bulls' big men.
Towering lock Lood de Jager and flanker Jason Jenkins went in between the posts to turn it around at 17-12 to the Bulls early in the second.
The Bulls' only lead of the game lasted two minutes as Stormers center Damian de Allende set up a try for fullback SP Marais with a break down the short side. The Stormers pulled away in the last half-hour with a fourth try to hooker Ramone Samuels, who made up for his earlier sin-binning for a late tackle.
Earlier, the Auckland-based Blues beat New South Wales 24-21 to extend an embarrassing run of losses for Australian teams against New Zealand opponents.
Despite the Waratahs going in as favorites as the leading team in the Australian conference, it was the Blues, last in the New Zealand conference, who held on through 19 phases over the closing minutes. The victory made it 38 consecutive wins by New Zealand teams against Australian teams over the last two seasons.
Winger Ben Lam scored three tries and took his season tally to 12 as the Hurricanes beat the Johannesburg-based Lions 28-19.
Lam came into the match with nine tries, level with Jaguares winger Emiliano Boffelli as the leading try-scorer, and touched down once in the first half and twice in the second to take sole possession of first place.
He shrugged off weak defense to score in the seventh minute, giving the Hurricanes a lead they held for the remainder of the match. By halftime the Hurricanes were seven ahead and they extended their lead to 28-7 with Lam's tries in the 44th and 53rd minutes.
The Lions narrowed the margin with late tries to Marnus Schoeman and Sylvian Mahuza but couldn't sustain the rally.
The match repeated the clash between the teams in Wellington in the 2016 final, which the Hurricanes won for their first Super Rugby title.