SYDNEY (AFP) - Western Stormers supplanted the Northern Bulls at the top of the Super 15 series this weekend with the ACT Brumbies, Canterbury Crusaders and Coastal Sharks keeping in the hunt for the playoffs.

The Stormers, who have never won the southern hemisphere provincial championship, hung on for a 19-13 win in Cape Town over the New South Wales Waratahs that further dented the Australian side's top-six playoff ambitions.

The Stormers lead the standings on points difference from New Zealand's Waikato Chiefs, who had a bye this weekend, while the Bulls are two points back after going down 16-11 to the Otago Highlanders in Dunedin.

The Brumbies tightened their grip on the Australian Conference with a storming second half to overcome the Hurricanes 37-25 in Wellington.

The seven-time Super Rugby champion Crusaders crushed the woeful Auckland Blues 59-12 to keep in touch with the Chiefs in the New Zealand Conference.

The Sharks are sixth overall after downing the Central Cheetahs 34-20 in an all-South Africa match in Bloemfontein.

Wallaby fly-half Quade Cooper played his first rugby of the season as defending champions Queensland Reds posted a bonus-point 34-20 victory over strugglers Golden Lions in Brisbane.

The Melbourne Rebels won away from home for only the second time in their two seasons with a 32-31 win over the Western Force in Perth on Sunday to leapfrog the Waratahs into third spot in the Australian Conference.

For the second consecutive week the Stormers were outplayed in the second half, but just did enough to see off the desperate Waratahs at Newlands.

The Stormers led 16-3 at half-time but were only able to pick up a single three-pointer in the second half, holding on in wet conditions for their 10th win in 11 matches. They have yet to earn a four-try bonus point.

The Highlanders dug in deep to pull off an upset win over the Bulls and lie three points adrift of the second-placed Crusaders in the New Zealand Conference.

It is the second straight year the Highlanders have proved to be the Bulls' bogey team, after ending their 19-match winning streak when they beat them in Pretoria last year.

They also put a dampener on Morne Steyn's celebrations in his 100th Super game for the Bulls as he was uncharacteristically off-target with the boot, missing a conversion and two penalties that could have changed the outcome.

Rookie fly-half Zack Holmes proved the difference as the Brumbies hit back to deny the Hurricanes after both sides scored four tries apiece.

Holmes, making his run-on debut after injuries to playmakers Matt Toomua and Christian Lealiifano, kicked four conversions and three penalties, as well as scoring a try, to give the Brumbies their first victory in Wellington for nine years.

The Crusaders, stung by criticism after losing to the Melbourne Rebels last week, smashed the Blues nine tries to two in Christchurch.

With their talisman All Blacks Richie McCaw and Dan Carter back to near their best, the Crusaders regained fifth place from the Highlanders while the Blues continued to languish near the bottom.

Former France fly-half Frederic Michalak scored 19 points as the Sharks kept alive hopes of a play-off place by prevailing over the Cheetahs.

Cooper, making his first appearance since rupturing knee ligaments at the World Cup in New Zealand last October, put in 40 minutes before he was replaced at halftime for the Reds.

Queensland scored four tries and raced to a 34-6 lead after 55 minutes before the Johannesburg-based Lions scored two converted tries by way of consolation.