Barking Road Runners Emma Botterill won the Handicap race at Barking Park with a personal best time of 28.29.
Daniel Plawiak was just behind in second place with John Laing bagging third spot in the rain.
Altogether six runners set personal bests and after four races Joyce Golder leads the series from Jason Li and Plawiak.
The next race is scheduled for July 1.
Ron Vialls and Botterill competed in the Victoria Park 10k finishing in 48.11 and 1:00.13 respectively.
Alison Fryatt, Golder, James Lowndes and Rob Courtier took part in the Phoenix longest day challenge, which involved running a mile every hour on the hour for 24 hours.
And Gabriele Grimaldi, Cristina Cooper and Trevor Cooper competed in the Chelmondeley Castle Triathlon, with Grimaldi finishing first in the elite race after swimming 1,500m, cycling 44k and running 10k.
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