Old Northamptonians suffered an agonising 18-17 defeat after missing a conversion to win the game.
James Grayson, son of Saints legend Paul, was unable to bisect the posts, leaving ONs disappointed after a valiant display.
Matt Love had given the home side the lead at Billing Road before the Lions responded with a penalty.
ONs lost Ben Briddon and Love to injury at the break but they soon scored again as Rory Seymour set up Alex Crofts for a try, with Grayson converting.
However, the Lions came roaring back with two quick tries and a penalty was also added to take them 18-12 ahead.
But it looked like ONs would win it when Chris McKee finished a push over, leaving Grayson with the chance to win it from the tee.
The conversion was narrowly wide though, meaning the hosts had to settle for a losing bonus point.
Meanwhile, Old Northamptonians IIs proved far too strong for their Peterborough counterparts running in nine tries in the 60 minutes played.
The Lions had arrived with just 12 players but were loaned three to make up a full team.
The ONs scorers in the 57-0 win were Simon Portwain (2),Ted Bunn (2), Andy Orbinson, Rhys Evans, Rob St Pierre, Dan Odita and Ben Dawson.
Dawson added five conversions and Bunn one.
Old Northamptonians IIIs lost 34-24 to Bedford Athletic IIs.
Scouts secured two bonus points, but couldn’t quite claim the victory they wanted.
The away side started well and took the lead after 10 minutes, when a cross-field kick by fly-half Adam Frost was gathered by Glyn Roff, who touched down.
Frost added the extras, but a yellow card reduced Scouts to 14 men and Matlock took advantage with an unconverted pushover try.
Soon after, they repeated the trick to put them in the lead.
The visitors were then on the back foot for the remainder of the half and conceded two further tries, which left the score at 24-7 at half-time.
An angry Scouts team took to the offence straight from the restart and a pushover of their own was touched down by Jordan Dolman.
Scouts then worked hard on keeping possession and a neat offload put Luke Reeves in for a score which Frost converted.
Scouts dropped the ball over the line after this but they drew level when Dolman grabbed his second of the afternoon.
A missed tackle allowed Matlock in for a converted score and Frost brought the scoring to a conclusion with a penalty.
Again, Scouts had the chance to win the match but two bonus points was their only reward.
Sharnbrook & Colworth 20
A determined display from man of the match Ash Brown inspired Heathers, but they were narrowly beaten by Sharnbrook & Colworth.
Heathens averted the spectre of uncontested scrums by loaning Sharnbrook & Colworth two front row players.
Sharnbrook went 10-0 up early on but Heathens responded with an impressive score as centre Mark Allison crashed over.
The second half opened in similar vein, but uncontested scrums were called on 50 minutes when one of the Sharnbrook props was injured.
What made it doubly unfortunate was that the injury was to the heel of veteran Heathens prop Martin Robson, who was on loan to Sharnbrook.
Sharnbrook extended their lead with a penalty after 57 minutes and went further ahead with a converted try two minutes later.
At the other end, some driving play eventually saw No.8 Dan Stonehouse drive over for a try to which Brown added the extras on 68 minutes.
And that was how it stayed as Heathens were beaten.
Next weekend, they remain in merit table action, taking on Mens Own IIs in a local derby at their Ashton ground with a 3pm kick-off.