The 26-year-old, who has 79 caps for his nation, electrified the crowd by sliding across the whitewash 19 minutes into the derby clash.
North, a back-to-back Guinness Six Nations victor in 2012 and 2013, capitalised out wide after a fine crossfield kick from compatriot Sam Davies.
However, the man of the match award went the way of Welshman Justic Tipuric after the 29-year-old flanker dazzled throughout, setting up Six Nations Grand Slam winner Scott Williams for the game’s opening try.
In the opposite colours of Cardiff, Wales fly-half Gareth Anscombe outlined his case to Warren Gatland for a starting berth in his side’s Guinness Six Nations opener against France.
The 27-year-old shined in the Autumn International campaign, notching up six points against South Africa, and he again proved his worth from the tee against Ospreys with two penalties and a vital assist with a sumptuous chip through to Wales U20 international Garyn Smith to score his side’s only try of the match.
The plethora of Welsh talent in action didn’t end there though as Scarlets got back to winning ways by getting the better of rivals Dragons 22-13 in the Guinness PRO14.
Veteran Wales and British Irish Lions hooker Ken Owens was handed the unusual starting spot at number eight, but the 59-times capped international showed his versatility by helping to guide his side to victory.
Tries in the match came courtesy of Wales U20 international Ioan Nicholas and Scotland Six Nations stalwart Sam Hidalgo-Clyne, who provided a spark from the replacements bench by initiating a tap and run and diving across the try line to seal the win.