Locks Heath Pumas were edged out of the Hampshire plate 22-17 by division one hosts Romsey.
The understrength Pumas raced into a 12-point lead with two tries by centre Steve Collins.
He then completed his hat-trick before Romsey dominated the second period to take the victory.
‘It could have gone either way,’ said Pumas manager Robert Woodford.
‘We had chances to win but knocked the ball on at crucial times.
‘It was our first loss of the season but I thought we did well considering we had a lot of first team players unavailable.’
Fareham Heathens had to work hard to beat Hampshire two strugglers Southsea Nomads 17-11 in atrocious conditions.
Johnny Stoppard grabbed both Heathens tries with Cam Guthrie kicking the rest of the points.
‘It was like playing rugby with a bar of soap,’ said Heathens coach Bernie Rhodes.