In a battle of two kickers it was Luther Burrell’s first-half try that proved the difference as Northampton Saints edged a nip-and-tuck contest at the Madejski Stadium.
London Irish centre Shane Geraghty kicked four second-half penalties to haul Irish back into the contest after Burrell’s third try of the Aviva Premiership Rugby season on the stroke of half-time.
However, Geraghty’s efforts were not enough as Stephen Myler produced a typically-composed display from the tee to land four penalties of his own.
The victory ensures Northampton have still been beaten just once since April – against Wasps in round two – while the Exiles have now lost four of their last six home games.
After a cagey opening ten minutes, the first points of the game came from the boot of Saints fly-half Myler in the 15th minute after a rolling maul was collapsed illegally.
Geraghty missed the opportunity to level the scores for the home side five minutes later after a penalty was awarded for the same offence.
The chance proved to be the only one Irish could muster in the opening 40 minutes, a tight half in which both defences offered few openings.
It wasn’t until two minutes before the break Saints got the crucial score, when England centre Burrell went over in the corner.
The decision had to be reviewed by the TMO after Burrell was brought down half a metre from the line but his outstretched arm was deemed to have done enough.
Myler converted the score to give the visitors a ten-point lead on the cusp of half-time and did have the opportunity to further increase that advantage a minute later.
However, the Northampton No.10 dragged a long-range penalty wide of the left-hand post, prompting referee Matthew Carley to call time on the half.
Just two minutes after the break Geraghty got the home side on the board with a magnificent penalty kick from just inside the opposition’s half.
He then converted another penalty, albeit a much simpler chance, in the 49th minute to bring his side within four points of Northampton.
But in the 54th minute three more points from the boot of Myler restored the advantage before Geraghty again responded with another close-range penalty for Irish.
Myler showed anything Geraghty can do he can do likewise as his long-range penalty attempt was successful in the 63rd minute.
Three minutes later, Geraghty scored his fourth penalty of the game and his 63rd point of the campaign.
With just three minutes left on the clock, Northampton missed the chance to finish things off when a poor pass from Burrell prevented full-back Ben Foden from gathering the ball when he seemed certain to score.
But Myler made amends two minutes later with his final penalty to put the visitors seven points clear as the final whistle blew.