Ulster scored three tries against the Blues as they claimed their first home victory in this season's Celtic League.
Ulster (15) 30
Tries: Maxwell, Feather, McCullough
Pens: Larkin 5
Cardiff (6) 14
Try: L Thomas
Pens: L Thomas 3
It was all penalties in the first half with fly-half Adam Larkin kicking Ulster into a 15-6 lead at the break.
The Welsh side reduced the gap to six points before tries from winger Andrew Maxwell and captain Campbell Feather put Ulster 25-9 ahead.
Lee Thomas went over for Cardiff before Matt McCullough sealed the points with a touchdown three minutes from time.
Both sides put out weakened outfits because of injuries and international call-ups
and, as a result, it was a scrappy and fairly uninspiring contest.
The opening score came from Ulster when Robin Sowden-Taylor was penalised at a
ruck and Larkin slotted the three points after six minutes, but the Blues almost
immediately responded with a Thomas penalty.
Ulster proceeded to put together some decent-looking work going forward and
were rewarded as the visitors responded by surrendering cheap penalties which
Larkin duly converted.
Three Larkin penalties put Ulster 12-3 up after 20
Thomas then narrowed the home side's lead just after the half hour with his
second penalty following a rare Blues sortie into Ulster territory.
But normal service was shortly resumed as an Ulster attacking maul, in
Cardiff's 22, ended with Deiniol Jones being sin-binned by referee Iain Ramage
for pulling the maul to the ground. Larkin duly converted his fifth penalty to
put Ulster 15-6 ahead.
Thomas again narrowed Ulster's lead with his third penalty, after 48 minutes.
But, just on the hour, Ulster made a breakthrough with an opportunistic try from
A Paul Steinmetz kick for the corner was missed by Blues full-back Matthew
Nuthall and Maxwell kicked on to score an unconverted try and put the home side
20-9 in front.
Feather, Ulster's skipper for the night, stretched his side's lead further by
making the corner after 71 minutes.
Thomas' 75th minute try was mere consolation for the visitors, especially as
McCullough bagged his side's third try three minutes later.
Ulster: B Cunningham, S Young, Bell, Steinmetz, Maxwell, Larkin, Campbell; McCormack, Shields, Moore, Longwell, Frost, McCullough, N Best, Feather (capt).
Replacements: Brady, B Young, Brown, Pfister, Doak, Mallon, Trimble.
Blues: M Nutthall; N Walne, S James, L Thomas, C Morgan; N Macleod, R Powell; J Yapp, G Williams, B Evans, D Jones, R Sidoli, N Budgett, R Sowden-Taylor, N Thomas.
Replacements: A Lewis, R Thomas, M Jones, M Lewis, J Malpas, R Smith, T Davies.
Referee: Iain Ramage (Scotland)