Despite a 9-0 lead at the interval the Blues lacked the composure needed to defend the advantage for enough time to build pressure on an ON's side playing down the slope in the 2nd.
Three first half penalties from Joe Daniel were never going to be enough unless the Blues could absorb the inevitable early pressure which a fired up Northampton side were looking to exert.
The Blues began the game strongly, playing down the slope and Joe Daniel almost scored in the second minute when the ball was moved left and only a desperate last ditch tackle prevented the try.
The tackler made sure the ball was not available quickly and was rightly penalised, and considering the offence was on the try line very fortunate not to receive a yellow card which the offence clearly deserved. Daniel kicked the penalty to give the Blues the lead and then added 2 further penalties as the Blues looked to build a lead.
With no further scores in the first half, ON's started the second half determined to quickly reduce the deficit.
This they did after 2 minutes when Kettering repelled an attack and turned the ball over only for them to lose the ball close to the try line and ON's gleefully pounced on the ball to score a converted try.
A second score soon followed and the belief visibly drained from the Blues as the home side pressed home their advantage.
Two further converted scores gave the home side a comfortable cushion and despite a late surge from the Blues ON's held on for a deserved bonus point win, as the Blues put in one of their most disappointing performances of the season.
Next week sees the return fixture at Waverley Road against Nottingham Paviors. The first match was a 60 point thriller as the Nottingham side scored the winning try in the 7th minute of injury time. This encounter has the potential to be just as exciting with both sides looking for points to climb the table.