Sonny Bill Williams stars as Chiefs crush Crusaders 40-16 in Super Rugby

Waikato Chiefs demolished New Zealand rivals the Canterbury Crusaders 40-16 to maintain their perfect start to the Super Rugby season.

The Chiefs ran in five tries to one, with the outstanding Sonny Bill Williams scoring one and setting up two more as the North Island side made it three wins from three.

It was the Chiefs' biggest win over the seven-time champions, confirming they are back to their best after winning back-to-back titles in 2012 and 2013.

The Crusaders, finalists last year, struggled to cope with Waikato's combination of speed and physicality, falling to their second defeat in three starts.

They were missing All Blacks Dan Carter, Israel Dagg and Owen Franks.

But they still fielded a strong side and coach Todd Blackadder will be looking for answers as his team licks its wounds during a bye next week.

Williams had an outstanding game for the Chiefs, including an intercept, a one-handed try and several pinpoint-accurate passes.

Waikato conceded three early penalties and were trailing 6-0 with a man down after 10 minutes when winger James Lowe was sin-binned for a dangerous tackle on Scott Barrett.

But they shrugged off the disadvantage as Aaron Cruden found a gap to spark a move that culminated in Williams spinning away from a tackler and stretching over the try-line.

The Crusaders then lost Matt Todd to the sin-bin, allowing Augustine Pulu in for a try from a Chiefs driving maul.

Waikato extended their lead when Williams intercepted a stray pass and set up a try for Charlie Ngatai, going into the break 22-9 up.

Andy Ellis kept the Crusaders in touch with a try after the restart, fooling the Chiefs' defence with a dummy after a patient build up.

But a period of sustained Chiefs pressure caused uncharacteristic panic in the Crusaders defence, when they tried to run the ball from their own try-line instead of kicking it clear.

The result was a turnover that led to Tom Marshall scoring the Chiefs' fourth try, blowing out the lead to 33-16.

It turned into a rout when a Williams' pass released Lowe down the wing for a fifth, and the Crusaders were lucky not to concede another before the siren sounded.