Stephen Myler won the battle of the boots with former team-mate Shane Geraghty as Saints secured a fine 19-12 Aviva Premiership victory at London Irish.
The Northampton No.10 ended the encounter with 14 points to his name, with Luther Burrell’s first half score also proving crucial.
Irish fought tooth and nail having gone in 10-0 behind at the break but they couldn’t break down the stubborn Saints rearguard.
In the end, a fine flying hit from George Pisi, which wasn’t the Samoan’s first of the day, forced a forward pass to fly out of play as the men in lime celebrated the victory.
Geraghty did rack up four penalties for Irish, who had won 22-19 at Leicester just a week earlier, but it wasn’t to be enough against the champions.
Instead, it was the Saints supporters who were singing at the final whistle, just as they had from the off as their side set the early tempo.
The visiting players responded and won a penalty at the first scrum to assert their authority against a confident home side.
And Saints were soon winning a kickable penalty in the Irish half as Halani Aulika was penalised for hands in the ruck. Myler missed from wide right.
The Northampton scrum was melting the Irish pack, despite the absence of injured England duo Dylan Hartley and Alex Corbisiero.
It was giving the away side a sturdy platform to build on and Irish were struggling to get out of their own half, conceding a string of penalties.
Myler kicked for the corner, before a lineout drive earned another shot at goal. This time, the fly-half went for it, and this time, he made it.
But going behind spurred Irish into action and they soon had a kick of their own, with Geraghty firing it wide of the posts.
Saints were forced into a change soon after as captain for the day Lee Dickson suffered a shoulder injury and Kahn Fotuali’i came into the action with just 15 minutes on the clock.
Irish slowly grew into the game but as they tried to put the pressure on George Pisi put in one of his piledriver tackles on Geraghty to wrestle the ball back for Saints.
It was a monstrous hit, reminiscent of the blows the Samoan landed on the former Saint at the Gardens back in April, and it swung the momentum back the way of the visitors.
They used it well, with Ken Pisi springing an attack from his own half and Burrell powering through Geraghty to slide over for the game’s first score.
The TMO took his time over awarding it, but with the ball planted on the line, the away side had their try, and Myler added the extras.
The fly-half was wayward with an ambitious penalty attempt just before the break as Saints continued to apply the pressure.
And they had another chance to score on the brink of half-time, but a flowing move from left to right ended in Ken Pisi being bundled into touch.
Irish started the second period desperate to make up for being nilled in the first and Geraghty’s boot soon made amends as he lashed a long-distance penalty through the posts.
The home side suddenly had a spring in their step and now it was Saints who were struggling to stem the tide.
Geraghty landed another penalty after Irish earned the call at the breakdown, and the gap was down to just four points.
Myler was soon stretching that lead though, as, to the annoyance of the home fans, referee Matthew Carley handed Saints a penalty at the scrum.
But the ebb and flow nature of the half continued as Geraghty responded, making the most of Jon Fisher’s high tackle on Luke Narraway to register the three points.
Again Myler issued a retort, superbly landing an effort from out wide to keep the scoreboard ticking over and keep Saints a converted try clear.
But yet again Geraghty reduced the deficit, with the referee’s whistle the overriding noise in the sparsely-populated stadium.
The blond-haired centre looked to bounce back with a drop goal, but his effort, under pressure from Fotuali’i, was horribly skewed.
And Geraghty was similarly wayward with a penalty soon after as the pressure continued to build on Saints.
The errors were starting to creep into the visiting side’s game, with Irish cranking up the heat.
But the Saints pack responded, turning on the power, and Irish crumbled under the strain.
That gave the backs a chance to fly forward but after coming within inches of the line, Burrell’s pass was behind Ben Foden, who couldn’t take it and knocked on at the last.
But Saints did at least have three points to show for their efforts soon after as the steady boot of Myler landed a penalty from in front of the posts.
Irish had less than two minutes to get a try and conversion to level the game, but they couldn’t do it as George Pisi had the final say with a vital tackle.
London Irish: Fenby; Lewington, Mulchrone, Geraghty, Short; Noakes, O’Leary; Court (Parr 61), Paice, Aulika (Cross 73), Skivington (c), Sinclair, Low, Cowan (Guest 61), Narraway.
Replacements: Stevens, Halavatau, Leo, Allinson, Sheridan, Ojo.
Saints: Foden; K Pisi, G Pisi, Burrell, North; Myler, L Dickson (c) (Fotuali’i 15); A Waller, Haywood (McMillan 75), Ma’afu (Denman 60); Lawes, Craig; Clark, Fisher (Dowson 65), Manoa.
Replacements: E Waller, Harrison, Hooley, Collins.
Referee: Matthew Carley