Wales ran in 5 tries to one from Canada to record a 41 points to 10 victory in Melbourne, and secure a bonus point.
The Welsh started hesitantly, falling behind in the 4th minute to a dropped goal by Bob Ross. But crucially fly-half Ross then missed a penalty with Wales down to 14 men after captain Colin Charvis had been set to the sin bin for a high tackle.
Wales came back through tries by Sonny Parker and Gareth Cooper, and with Harris adding both conversions and two penalties led 20 - 3 at half-time.
Further tries from Kark Jones, Charvis and Gareth Thomas, all converted by Harrissecured the Welsh victory, but the Canadians had the consolation of a try by Kevin Tkachuk, converted by James Pritchard.
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