The Blues might have failed to cross the whitewash - something the Dragons had no worry with as Will Harries touched down just before the half hour mark - but it didn't matter as Halfpenny kicked five penalties for victory, Rhys Patchell adding one of his own and Gareth Davies booting over a drop goal.
The result saw Cardiff Blues climb up one place to ninth in the table and it was the result rather than the performance that Davies was most concerned with at Arms Park.
"It was a valuable win for us," he said. "It was valuable that we won and it was valuable that we kept the bonus point away from them.
"It wasn't a pretty win. It was interesting to watch at times, but what was evident was the tenacity and control we showed up front, in the second half in particular.
"The first 30 minutes of the game was a bit more like what we wanted to achieve, but after that things went a little bit wayward.
"But what we did do in the second half was get control of the ball up front. We carried hard off the edges and built pressure for Leigh to kick the goals. But we can be tidier than that.
"The result was all-important. We have got a bit to do in the league and we know that, but slowly but surely we have been getting better and it's about control of the ball.
"We are getting plenty of possession, when we get the opportunities we have got to finish them off. We will keep building the player's confidence and skills to be able to do that."
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