The Crusaders made it three tight wins in a row with their hard-fought 16-13 victory over the Bulls at AMI Stadium tonight, the forwards putting in an heroic effort to combat the big South Africans.

The defending champions are heading up the table thanks to their wins over the Waratahs, Stormers and Bulls and now have a bye and a deserved rest as they contemplate a three-match tour of South Africa.

One piece of bad news for the Crusaders concerns centre Casey Laulala, who broke his left arm and could be out for the rest of the season. It is the same arm that Laulala broke last year which kept him out most of the Air New Zealand Cup with Canterbury.

It is terrible luck for Laulala and the Crusaders and comes after Corey Flynn re-broke an arm in round two against the Brumbies which has sidelined him for the rest of the season.

An early try to Isaac Ross, converted by Stephen Brett, who kicked three from three plus a drop goal tonight, put the Crusaders 7-0 up.

A kick into space from Leon MacDonald was claimed by left wing Colin Slade and he popped the ball quickly to Ross who dived over. One lucky punter would have been happy - a bet of $500 was made with the TAB that Ross (paying $30) would score the first try of the night.

A Brett penalty soon after made it 10-0 and the Crusaders were playing all the rugby. The Bulls, unbeaten before being thrashed by the Highlanders in Palmerston North last week, were looking off-colour again.

They allowed the Crusaders ball runners space and time and were reluctant to climb for high kicks.

However, they got their act together just after the half hour when Wynand Olivier, broke through missed tackles by Tim Batemand and MacDonald and offloaded to right wing Akona Ndungane, who went over in the corner.

Steyn missed the conversion from the sideline but the Bulls were back in the game at 10-5. It seemed it was the Crusaders turn to go off the boil after having so much possession and territory for the first 30 minutes.

After the break a sharp Brett drop goal extended the Crusaders lead to 13-5.

Openside flanker George Whitelock, back for the Crusaders after missing last week's match against the Stormers with a cut thigh, was luckily on hand to outjump Ndungane and defuse a dangerous kick near the try line.

However, the right wing wasn't to be denied and he scored his second try after more missed tackles for the Crusaders. Olivier, in his 50th Super rugby match, was again the provider.

Steyn again missed a difficult conversion and the score was 13-10.

A high tackle by Ross on replacement hooker Derick Kuun gave Steyn the opportunity to level things up and he took full advantage with his penalty.

A high tackle by replacement flanker Pedrie Wannenburg on Bateman gave Brett a chance to put the Crusaders ahead and he slotted it, much to the relief of the Crusaders and 13,500 crowd.

Fine work by MacDonald to shepherd the ball over dead ball line assisted the Crusaders cause and then the forwards took control, keeping possession and a series of pick and goes to wind down the clock.

The heroes for the Crusaders were the forwards, who outplayed their vaunted Bulls opposites. They had an edge in the lineouts and scrums (winning two tightheads) and were more urgent and effective at the breakdowns.

Lock Brad Thorn had a huge game, putting in two memorable tackles and taking control of the lineouts against supposed expert Victor Matfield.

Tighthead prop Owen Franks, in his first start for the Crusaders, was immense. He never took a backward step in the scrum, yet still had the energy to appear in the loose and run the ball back with agility and skill.

Captain Kieran Read, with his direct running, was another to impress, as was lock Ross.

Head coach Todd Blackadder said afterwards: "That was a huge result for us. We're battered and bruised but will take heart from another gutsy effort. It was exactly what we needed heading into the bye and our trip to South Afrcia.

"The courage of the guys in this team cannot be faulted against a team with so many Springboks in it."

Crusaders - Try: Isaac Ross. Con: Stephen Brett. Pens: Brett 2. Drop goal: Brett.
Bulls - Tries: Akona Ndungane 2. Pen: Morne Steyn.

HT: Crusaders 10-5.

Crusaders: 1. Wyatt Crockett
2. Jason Macdonald (16. Dan Perrin 76th minute)
3. Owen Franks
4. Brad Thorn
5. Isaac Ross (18. Michael Paterson 62)
6. Kieran Read (c)
7. George Whitelock
8. Thomas Waldrom
9. Kahn Fotuali'i (20. Tyson Keats (72)
10. Stephen Brett
11. Colin Slade
12. Tim Bateman (21. Ryan Crotty 74)
13. Casey Laulala (22. Adam Whitlock halftime)
14. Jared Payne
15. Leon MacDonald (19. Nasi Manu (77)

Reserves not used:
17. Peter Borlase