Rugby Union: St Peter's prey on giant: Robert Cole on the fifth round of the Swalec Cup in which Cardiff fell from grace

THE scoreboard operator at the Arms Park has a lot to answer for. As St Peter's warmed up for what was expected to be a comfortable home win for Cardiff over their Third Division neighbours, the visiting players could not help but notice the digital socreboards at either end of the ground.

'They had Cardiff 000, St Peter's 00,' the St Peter's coach, Laurence O'Brien, said. 'I thought, 'you cheeky bastards'. They may have scored 107 points against Plymouth Albion, but they certainly weren't going to do that against us.'

O'Brien was quite right, his side going on to record the most famous victory in the 23-year history of the Welsh Rugby Union Challenge Cup, now known as the Swalec Cup, by beating Cardiff 16-14 in what was the home side's 100th tie.

Winners five times and finalists on three further occasions, Cardiff should have known better than to gamble with selection for a one-off occasion by playing only four first-team regulars.

'As soon as we heard the Cardiff team we felt there was a possibility of us winning. That gave us quite a boost,' Simon Harris, the St Peter's captain and full-back, said. 'It was always going to be a game that Cardiff weren't going to take seriously. They underestimated us and we had the last word.

'We're one of the few clubs left at which the players don't get anything for playing. We're paying to play. I don't care how much money some teams are offered in bonuses, you can't buy success or memories like beating Cardiff.'

If Cardiff's team selection was the first boost of confidence for Harris and his team, there was another in the second half when the home side made what appeared to be a blatant tactical substitution by replacing the out-of-sorts Geraint Lewis with Adrain Davies, leading scorer in the Heineken League, at outside-half.

Davies kicked three penalties but failed to convert Mike Hall's 77th-minute try which would have taken the game into extra time, while his last-ditch penalty attempt would have won Cardiff the game had he succeeded.

But rather than worry about the controversial appearance of Davies, St Peter's took it as a sign that Cardiff were panicking. As for Cardiff, who had averaged 54 points a game in their last six matches, they targeted the referee, John Groves, as an escape route.

'I'll probably get shot for saying it, but you can't have a pounds 5 referee in a pounds 20,000 competition,' Alex Evans, the Cardiff coach, said. 'I can't say much without being critical of the referee. St Peter's did all they could without getting caught and they got away with plenty. We should have done the same thing but our players aren't trained to break the laws.'

There were no other shocks in the fifth round, although there was plenty of hard work needed from the senior clubs to suppress local hosts. Neath had to recover from a 10-0 half-time deficit before beating the hitherto unbeaten Pyle

20-10, while the holders, Llanelli, were six points adrift at Kenfig Hill before three tries brought them a 17-6 win.

Newport survived at Pontypool United 10-0, while Bridgend ran out 12-0 victors at Fleur de Lys. It was all close stuff, but nothing as dramatic as at the Arms Park.