The Crusaders' Super Rugby title defence has struck an early season speed bump after going down 25-17 to the Highlanders in a rollicking South Island derby.

The Highlanders made it three wins from three, all in Dunedin, to start their campaign while the Crusaders slump to a two win-two loss record.

Having only lost once on their way to an eighth title last year, questions will be asked about the depth of a Crusaders team who have lost twice on the trot and are missing a swag of their key All Blacks.

They couldn't match the intensity of the hosts on Saturday, particularly a ferocious defensive line led by No.8 Luke Whitelock.

Slighty fortunate to be 14-10 up at halftime, the Highlanders were the better side in the second spell to maintain their perfect record under new coach Aaron Mauger.

Their winning trot under the Dunedin roof has stretched to 10 and if they can continue that, the Highlanders appear capable of mounting a serious title threat.

First five-eighth Lima Sopoaga scored one of their three tries and finished with 15 points while winger Tevita Li was a constant attacking threat.

The Crusaders hadn't lost consecutive games for three years.

They were clearly missing captain Sam Whitelock and vice captain Ryan Crotty, who both suffered concussion early in last week's loss to the Hurricanes.

Missing 29 tackles was a killer for the Crusaders, whose cause also wasn't helped by rulings either side of halftime.

An apparent try to Jordan Taufua was ruled out following a replay which referee Glenn Newman says showed the ball being spilled forward earlier by Tim Bateman. The fuming Crusaders believe the ball had been stripped from his grasp by a defender.

After the break, Highlanders winger Waisake Naholo was shown a yellow card for a head high tackle on Heiden Bedwell-Curtis which was so blatant that it could have easily been red.

The hosts held firm during that 10-minute period and even created a try to reserve flanker Elliot Dixon to push them nine points clear.

Bryn Hall crossed for the Crusaders following a brilliant Manasa Mataele chip but two Sopoaga penalties were the remaining points.

Sopoaga and Liam Coltman crossed in the first half for the hosts after Crusaders winger George Bridge opened the scoring with a brilliantly-worked try.