The Blue and Blacks had the better of the first half exchanges but only led 10-6 at the break.
Both teams squandered gilt edged opportunities to score tries which meant the final outcome was never guaranteed for Cardiff.
Fly half Gareth Thompson opened the scoring in the second minute with a 40m penalty and when captain Joe Tomlinson was driven over from close range six minutes later, it looked like the Ravens were going to be in for a long evening.
Joseph Scrivens pegged back three points with a well struck penalty but dogged defence from the visitors held Cardiff at bay. The experienced second row pairing of James Down and ex-All Black Jarrad Hoeata were prominent with ball in hand but Cardiff couldn’t penetrate the Bridgend defence.
Even when Bridgend were down a man due to flanker Adam O’Driscoll being in the sin bin, Harri Millard was unable to put an unmarked Ceri Young clear.
Scrivens knocked over his second penalty of the evening just before the break to leave his side still in the hunt at halftime. The fly half, who impressed throughout with his game management, pulled his side to within a point soon after the re-start before a quick tap by Rhun Williams saw the Cardiff full back catch Bridgend by surprise. He darted his way over to score wide out.
Replacement David Bird increased the lead in the 55th minute with a penalty but Bridgend still had chances to snatch the spoils.
Tom O’Flaherty broke free and off-loaded to Mike Powell but the flying winger got the speed wobbles just short of the try-line and fumbled the ball to see the chance go begging.
Scrivens slotted his fourth success of the night to give Bridgend further hope but when the visitors were frivolous with another overlap in the dying stages, the Ravens were left to rue what might have been.
Scorers:
Cardiff: Tries: Joe Tomlinson, Rhun Williams; Con: Gareth Thompson; Pens: Thompson, David Bird.
Bridgend: Pens: Joseph Scrivens (4)
