In the morning, the two leaders had been level on championship points, but Swansea were ahead by virtue of having scored 20 tries to Cardiff's 19. But the looseness of Pontypool's defence allowed Cardiff to reverse that position, even though Swansea also won, beating Newport 16-9 at Rodney Parade.
The rain that makes Wales so green and glorious, can also make its rugby depressingly grey. And this was the kind of sodden afternoon made for primitive tactics and thudding boots.
With a kick like a mule, Mark Ring, the Pontypool captain who used to charm by the subtlety of his running, is now a master at exploiting these conditions. In the opening stages he thumped one ball through after another, wasting the first shots, which ran harmlessly out of play, but then finding his range with precision to force Cardiff, under duress, to touch down beneath their posts.
This looked like being the pattern of the game, for Cardiff found it surprisingly difficult to break out of their own half under the bombardment.
But neither could Pontypool, lacking their old physical power, press home the advantage. Their pressure brought no points, and once Cardiff managed to break the spell and move upfield, the combination of their strong back row and the persistence of their hooker, Huw Bevan, in the loose brought a succession of scores.
The first try, after 15 minutes, came from the No 8 Emyr Lewis, who went through untouched to the Pontypool line as though protected by an invisible force field. Bevan nimbly broke on the right for the second.
And after another forward build-up by the flanker Hemi Taylor, Simon Hill was sent through on the left. With two conversions and a penalty from Adrian Davies, Cardiff were 22 points up at half-time.
From that point Cardiff could simply pick the opportunities they were offered as Pontypool became increasingly depressed and frustrated. Their scrum-half, Andy Booth, darted over between the posts, while Steve Ford ran 100 yards for his try, Colin Laity also scored from deep, and Simon Hill slid over in a shower of spray for his second. Davies added another penalty and three conversions.
Cardiff: C John; S Ford, G John, C Laity, S Hill; A Davies, A Booth; A Lewis, H Bevan, D Joseph, S Roy, D Jones, H Taylor (capt), E Lewis, M Budd.
Replacements: N de Maid for W Morris (30min); I Wilkinson for Mruk, (70min).
Pontypool: J Williams; S White, P Taylor, Mark Taylor, B Taylor; M Ring (capt), W Morris; M Jenkins, L Woods, J Jones, L Mruk, C Billen, G Taylor, M Matthews, Matthew Taylor. Replacements: H Stone for D Jones, (56min).
Referee: H Lewis (WRU).Reuse content