Jonny Wilkinson came through his latest comeback with flying colours as he set out to prove his form and fitness to British & Irish Lions boss Clive Woodward.
Wilkinson successfully negotiated 46 minutes of Premiership action for Newcastle after recovering from a knee injury and taking over from Michael Stephenson shortly before the break.
The England captain did so with familiar efficiency, kicking three penalties and a conversion, even if he was slow to get off the floor following a bang on the head in one second-half tackle.
The only thing he could not manage was to repeat his World Cup heroics. A missed drop-goal and long-range penalty in the last five minutes meant Northampton held on for a win that goes a long way to ensuring their survival in the Zurich Premiership.
The Saints held their nerve after important tries from Chris Hyndman and Corne Krige just before half-time, and held on to the lead thanks to three nerveless penalties and two conversions from Shane Drahm.
Wilkinson took over the goalkicking after Dave Walder's two early penalties and England's World Cup winning fly-half also converted a second-half try from Jamie Noon that briefly threatened to turn the tide.
Despite picking up a bonus point, Newcastle's defeat means that they still need a last-day win against London Irish to make certain of their own safety - and give Wilkinson some extra game time.
They need to finish eighth or better in the table to go into the wildcard competition to give Wilkinson two extra post-season games before the Lions' warm-up game against Argentina on May 23, the deadline for him to convince Woodward to add him to the 44-strong squad named last Monday.
Northampton looked short of numbers going into the game with Andrew Blowers denied the chance to end his Saints career with a flourish by injury and rookie scrum-half Ben Jones thrown in at the deep end after Johnny Howard was dropped following last weekend's defeat at Bath.
But they had more punch up front than Newcastle's lightweight pack - despite the return of Colin Charvis in the back-row - and the visitors were also without double World Cup winner Matthew Burke, forcing Walder to move to full-back with Mark Wilkinson keeping brother Jonny's fly-half shirt warm.
The Falcons have not travelled well this season and struggled to make an impression early on as Walder and Drahm both missed with kickable shots at goal.
Drahm, though, found the target from two metres inside his own half after 10 minutes and followed up with a superb effort from wide on the left after a sustained Northampton attack led by Bruce Reihana and John Rudd down the right.
The advantage was immediately trimmed as Walder drilled over 24th and 28th minute penalties and Newcastle's best attack so far saw Jamie Noon and Mark Mayerhofler put Michael Stephenson within five metres of the line before the wing was brought down by Ben Cohen.
Stephenson was helped off, giving Wilkinson the chance to launch his latest comeback earlier than expected, initially lining up outside brother Mark in the centre, then switching to fly-half.
He thumped over a penalty within three minutes of taking the field and another with the last kick of first-half injury time.
But by then Northampton had established control with the help of some typically forceful running from Cohen, who set up the field position for two crucial tries.
Newcastle ran out of defenders on the left with Chris Hyndman touching down in the corner - then Newcastle lost control of the ball at a scrum on their own line with Krige pouncing on the ball and Drahm converting both tries for a 20-12 interval lead.
Defensive errors, though, have cost Northampton dearly this season and they made a costly one four minutes into the second half that allowed Noon to cut through a gap and shake off a couple of half-hearted tackles.
Wilkinson's inevitable conversion closed the gap to a single point and the Saints suffered another blow when centre Mark Stcherbina was stretchered off with a suspected broken leg.
The fingers were crossed for Wilkinson, too, when he was slow to get up, holding his right shoulder after taking the ball into contact on the hour.
He recovered quickly though, putting Newcastle in front for the first time in the game with his third successful penalty before Drahm's 66th minute effort edged Northampton back in front 23-22.
The crowd held their breath when Wilkinson dropped back to fire off a right-footed drop-goal from closer range than the one which beat Australia in the dying seconds of the World Cup final 17 months ago.
He was well wide, though, and a testing 40-metre penalty also drifted wide of the left hand post two minutes from time to show he is human after all.