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.
Wales Under 20 travel to Newcastle on Friday to face England at Kingston Park. With the likes of Jack Dixon and Ashley Evans returning to the squad, it's arguably the strongest side head coach Byron Hayward has put out in the tournament so far. WRU TV previews the game with Defence Coach Richard Hodges and captain Steffan Hughes.
Wales head coach Warren Gatland gives an exclusive interview to WRU TV after naming his side to face England in the RBS 6 Nations at Twickenham on Sunday. Gatland has recalled British & Irish Lions duo Jonathan Davies and Alun Wyn Jones to his side while Rhys Webb retains his place at scrum half.
Scrum half Rhys Webb and lock Jake Ball both made their first Wales starts in last Friday's win over France at the Millennium Stadium. They talk exclusively to WRU TV's Luke Broadley about their experiences of the day.
Wales Women's Head Coach Rhys Edwards has made three changes to his side to face France at Aberavon on Sunday, where he expects his side to be given a tough time against one of the best teams in the world.