The game was well refereed by James Jones (Bridgend), but it ran until the 53rd-minute of the second half when Rhiwbina replacement Gavin Harris went over and another replacement Alex Kerr landed a tricky conversion with the last act of a magnificent match.
Within the 55 points scored, the lead changed hands seven times and both sets of players and coaches can take credit for a wonderful display when fitness levels were tested to the full.
Two players stood out with wonderful, yet contrasting displays. Fly half Dan French of St Peters was a menace every time he touched the ball, while big Rhiwbina No8 Pat Howell was simply awesome.
St Peter’s opened with French cleverly sending hooker Tom Nolan over, but fly half Josh Davies replied as he sent his hooker Josh Madley clear and centre Richard Saltmarsh converted.
Back came ‘The Rocks’ as wing Gareth Norman crossed and French converted only for Saltmarsh to power through and add the conversion.
It was nip and tuck and St Peter’s centre Sonny Driscoll burst clear to score with French converting, but prop Paul Smith scored a superb Rhiwbina try and Saltmarsh goaled for 21-19 interval lead.
It was a thrill a minute in one of the best games of the season, yet it was 67 minutes before St Peter’s scored a magnificent long-distance try from Norman and full back Ryan Jones added a penalty for a 27-21 lead.
That appeared it, but the clock ticked on and Rhiwbina never stopped attacking. There were 13 extra minutes played with floodlights on when Harris scored and with Saltmarsh having limped off, Alex Kerr had the task of winning the match, which he did with the conversion.