South African rugby has two major titles to defend in 2011, and the champion Bulls’ performance in the restructured Super rugby competition will likely give an indication of the Springboks’ chances of a second straight World Cup title.

The Springboks-filled Bulls team are aiming for a third straight Super Rugby crown. Only New Zealand’s Crusaders have achieved the feat before.

South Africa also hopes for consecutive World Cup wins when a grueling southern hemisphere season closes. No team has ever defended the William Webb Ellis trophy.

For a third triumph in a row, and a fourth in five years, the Pretoria-based Bulls will have to hold off an extended challenge at home with the new-look and expanded Super 15 reshuffling teams into national conferences.

It means more local derbies. In South Africa, that means more bruising, physical encounters — which could have repercussions for the national team in rugby’s most important year.

The Bulls open their Super 15 campaign away at the Lions, of nearby Johannesburg, the modern version of the historically fierce Northern Transvaal-Transvaal derby.

There’s also Cape Town’s Stormers, the 2010 Super 14 runners-up, a Sharks team from Durban hungry to build on a domestic Currie Cup title and the Cheetahs of Bloemfontein — a team that relishes its constant underdog status.

“It’s a whole new ball game,” said Stormers coach Allister Coetzee. “Local derbies are always tough, physical, closely contested affairs. It’s is going to be a dogfight for that top spot.”

The Bulls are in best-possible shape for the battle after influential scrumhalf Fourie du Preez returned from injury and Bjorn Basson and Chiliboy Ralepelle were cleared of blame in their failed doping tests.

Du Preez, the Bulls’ tactical pivot alongside flyhalf Morne Steyn, has recovered from a long-term right shoulder problem to renew his combination with points machine Steyn.

Basson’s attacking flair, underlined by a hat-trick of tries in preseason on his Bulls debut, complements a powerful forward pack and the scrumhalf-flyhalf playmakers.

Captain Victor Matfield again leads a fearsome group up front, with the Bulls’ depth and experience epitomised by the presence of four Springboks second-rowers: Matfield, Bakkies Botha, Danie Rossouw and Flip van der Merwe.

Basson is the only new addition to the Bulls, as coach Frans Ludeke opted for minimal changes to a proven team.

“If every guy does his bit and believes in what the team does, success will follow,” flanker Dewald Potgieter said. “The advantage of the Bulls is that everybody buys into what we do, and how to win games.”

It could also be a final Super Rugby season for 105-Test veteran Matfield, adding extra incentive.

The Stormers, with a string of Springboks of their own, failed at the final hurdle in both the Super 14 and South Africa’s Currie Cup last season.

With the Super 14’s best defense in 2010, the Stormers have also changed little, relying again on centers Jean de Villiers and Jaque Fourie and wings Bryan Habana and Gio Aplon to provide an attacking thrust alongside the tireless tackling and ball carrying of captain Schalk Burger.

“We have a settled senior squad that has grown and learned from their experiences last year,” Coetzee said after the Stormers underperformed in both finals in 2010.

Led by up-and-coming flyhalf Patrick Lambie, and South Africa captain John Smith, the Sharks blend youth and experience.

Bulldozing flanker Willem Alberts also had a breakthrough season last year and was rewarded — like Lambie and winger Lwazi Mvovo - with a first Springboks cap for the northern hemisphere tour.

They operate behind a scrum anchored by Smit, Tendai ’Beast’ Mtawarira, Bismarck du Plessis and his brother Jannie — all experienced internationals. Like Matfield, it could be a farewell season for Smit.

The Cheetahs’ hopes hinge on the knee ligaments of ’pocket-rocket’ flanker Heinrich Brussow and the experience of fellow Springboks loose forward Juan Smith.

Last year, Brussow’s season-ending knee injury seriously hampered the Cheetahs, and their season never reached any great heights.

However, the Cheetahs thrive on taking down bigger South African teams and a season of increased derby matches could suit the men from the Free State province.

The Lions are South Africa’s — and maybe the Super 15’s — most intriguing team.

Following last year’s 0-13 season, the worst-ever in Super Rugby history, the Lions have been revived by two billionaire businessmen and a former All Blacks coach.

The injection of money from Robert Gumede and Ivor Ichikowitz - and the influence of new coach John Mitchell — turned the Lions around at the end of last year.

The team has added highly rated winger Lionel Mapoe and attacking fullback James Kamana of New Zealand — who failed to make the Crusaders Super 15 squad — among a string of new signings. One of them, South Africa’s 2007 World Cup-winning flyhalf Butch James, will join in May.

But having hit rock bottom in 2010, the Lions’ renewed belief and attacking — and at times carefree — style under Mitchell could upset any team.