The Chiefs have now scored 20 tries in posting successive wins over the Bulls, Highlanders, Brumbies and Crusaders to emerge as firm contenders for the play-offs.
Despite the result, the Crusaders retain the championship lead as they have a seven-point buffer over the second-placed Sharks while the Chiefs move into provisional third on the table.
The Crusaders were ambushed by a cohesive Chiefs side which scored two unanswered tries in the first half, one of them while it was a man short after lock Toby Lynn was sin-binned for persistent infringing.
Chiefs skipper Mils Muliana said first five-eighth Donald had played a brilliant game and his tactical kicking to put the ball behind the Crusaders' defence had paid off.
"What a great atmosphere in front of a packed crowd and I'm proud of my boys - they really stuck to it and to beat a team that has been unbeaten this year was very pleasing.
"We're building some momentum now and hopefully we can carry it on next week.'' Crusaders captain Richie McCaw said the Chiefs had outplayed his side.
"We made mistakes and they capitalised on them - they just had more intensity everywhere.
"I don't know why but we just lacked numbers at the breakdowns, the ball we were getting was quite slow and we struggled to get out game going.
"They had pretty good defence which inhibited our game.''
The Chiefs, taking a leaf out of the Crusaders' manual, recycled the ball efficiently and confidently retained possession - a pattern they retained throughout the game.
The Crusaders were unable to tidy their game up in the second half, although there was a glimmer of hope when they scored a deserved try through halfback Andy Ellis after 47min.
Minutes later, it seemed that they had cracked the Chiefs defence once again after fine build-up by Scott Hamilton, Corey Flynn and Sean Maitland, but substitute Nasi Manu lost the ball forward as he tried to slam the ball down for a try.
For once, there was nothing left in the Crusaders' bag of tricks and the Chiefs were able to lock them out.
Crusaders centre Casey Laulala was stretchered off wearing a neck brace after he was involved a head clash with Dwayne Sweeney late in the game.
The Chiefs won last year's corresponding fixture with the Crusaders 30-24 in Christchurch.
Chiefs 18 (Sitiveni Sivivatu, Simms Davison tries; Stephen Donald 2 penalties, conversion), Crusaders 5 (Andrew Ellis try). Half-time: 18-0.
