Harpenden find themselves bottom of the Herts Cricket League Premier Division after a second defeat.
They had posted 218 against Old Owens thanks to a pair of 48s from Danyaal Khalid and Andrew Neal, the pair putting on the home side's best partnership of 53, while Jake Pankhurst finishing on 39 not out.
However, the Potters Bar-based side took the game away from Harps with a first-wicket partnership of 189, winning by two wickets.
Radlett meanwhile managed to get a game played, their first two fixtures being washed out, and they had a completely opposite outcome.
They beat Hertford by nine wickets at Cobden Hill, bowling the away team out for 167 with Koby Cornwell taking 3-40 and Anthony Hill 2-23.
But like Old Owens, it was the opening batsmen who sealed the victory, Fraser Crawford the only man to depart after making 37 in an opening stand of 73.
Dominic Chatfield finished on 63 not out and Josh De Caires unbeaten on 64.
Shenley Village sit top of the Championship after a 37-run success over Hemel Hempstead Town but St Albans are up to third after defeating Reed by three wickets.
Ben Adshead took 3-15, Jamie Regan and Connor Mitchell bagging two wickets each, and then Regan (32) and Will Bancroft (26) led the reply, crossing the line in the 33rd over.
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