Superior fitness proved telling as Harpenden found an extra gear late on to defeat Hemel Hempstead 54-31 in an exhillirating London North West Two derby.
There was little to choose between the sides in the first period as they traded scores.
But by the end Harps had scored eight tries in a 13-try thriller, Ollie Mann kicking six conversions.
Adam Wilkinson led the way in the scoring charts with a hat-trick, while Luke Barber notched two and there was one each for Michael Goode amd George Attfield.
A penalty try, which brings its own conversion these days, completed the scoring.
Referee Tony Leake had no difficulty in supervising two teams who played disciplined rugby throughout, and it was a joy for both sets of supporters to see a fast-flowing game.
Harpenden, who are second in the table, will look to continue their perfect record when they travel to league leaders HAC on Saturday.
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