Coach Keith Braithwaite's side ended a three-match losing streak, and Otago bore the brunt, as Canterbury makes a belated attempt to reach the top four playoffs.
Otago did battle from the kick-off, and won a fair share of initial ball possession, but where Canterbury created controlled build-ups, Otago was often content to hit long balls for Regan Coldicott to chase.
With centrebacks Tom Schwartz and Julyan Collett in unforgiving form, few real opportunities were created.
It took Canterbury 28 minutes to breach Otago's defence, and neutrals applauded the quality of cross delivered by Louie Bush, and the well-timed run into space and spring-heeled leap that earned Ken Yamamoto a clinically executed headed goal. As has so often happened this season, while Otago was reeling, Canterbury did it again.
Minutes later, Ashley Wellbourne evaded two attempted tackles and drilled in a low shot. Keeper Liam Little got a hand to it but could not prevent the ball trickling over Otago's goal line.
As expected in a derby between traditional rivals, there were some crunching tackles. One left Otago fullback Craig Ferguson in agony, as an over-the-top challenge went unpunished.
Referee Campbell Kirk-Waugh waved on a tough tackle by Victor da Costa, then possibly over-reacted when Scott Gannon tackled All White Aaron Clapham, who bounced back up, apparently unharmed. But the referee brandished a red card and Gannon headed for a 66th-minute shower.
Fresh substitute Andy Barton came on and made scoring look easy, with a shot drilled past Little, then it was retrieval time again, as Little had to dig a booming shot from Yamamoto out of his net, and at 4-0 after 75 minutes Otago looked scuppered.
But as is often the case, 10-man Otago dug deep and competed well in the sweltering heat. Aajay Cunningham who earlier hit the Canterbury crossbar, dazzled on the left wing, Aaron Burgess showed class and true grit battling through attempted tackles, and at last, Coldicott perfectly timed his run on to a Seamus Ryder pass, and slammed in a spectacular shot on the run.
Just too little, too late, and amid a flurry of substitutions the match finished with Otago panting until the final whistle, and Canterbury, with Clapham as the hub, stroking passes around to run down the clock.
Otago coach Richard Murray said: ''They were eventually too good for us, on the day, but there was some inconsistency in refereeing, and after some tough tackles by both sides, we were unlucky to lose Scott Gannon, and from then on, 10 men were always going to struggle.''
Canterbury coach Keith Braithwaite had a yard-wide smile, as he complimented his side's battling qualities, the steady performances of his centre backs, calm control of Clapham, Russell Kamo, who was wherever the action was thickest, and the skills of Yamamoto, whose two goals illuminated the contest.
Ken Yamamoto 2, Ashley Wellbourne, Andy Barton