It was the 14th league win for Cardiff, but Newbridge put up a brave show and led 17-12 at one point.
Cardiff tries came from forwards James Goode (2), Chris Purcell and James Malpas with a penalty try and other touchdowns from backs Leon Andrews, Richard Jones and Liam Roberts. Andrews converted one and replacement Chris Anderson goaled six.
Newbridge, with several new faces, scored tries by wing Mark Addis and forwards Leighton Davies, Tom Lampard and Stuart Coles with a conversions each by fly half Ross Watts and full back Ross Jones.
Tonight (Wed) Bedwas entertain Pontypridd (7.15pm) with the return at Sardis Road on Saturday.
The WRU has teamed up with Crawshay's to tour Georgia in June. The side, which will be called the Crawshays WRU President's XV, will play Emerging Georgia twice, in a tour which supports the Welsh Government's efforts to grow relations between the two countries.
Wales Sevens are looking to re-group after a disappointing tournament last time out in South Africa. The next double leg in New Zealand and Las Vegas offers Gareth Williams a chance to redeem themselves.
Wales Women's head coach Rhys Edwards was at Llandovery to see the conclusion of an entertaining Women's Regional championship where any one of three teams were in contention for title glory on the last day of action.