Jonny Wilkinson could be a doubt for England's Six Nations campaign after his comeback was curtailed by what appeared to be a recurrence of his shoulder injury.
England's World Cup hero went down in a heap near the touchline on 53 minutes after attempting a tackle on Saints winger Bruce Reihana and underwent treatment on his neck and shoulder for four minutes before finally getting to his feet.
There was no way he could continue and the fly-half looked a disconsolate figure as he was helped off the field. He was replaced by the man whose place he had taken, Dave Walder, and he went on to score Newcastle's match-winning try.
Wilkinson only discovered he was making his eagerly-awaited return 45 minutes before kick-off when referee Ashley Rowden declared the Kingston Park pitch fit after a severe overnight frost. That was a big relief to the capacity 10,000 crowd, who were desperate to see their favourite play his 99th Premiership match, five weeks on from his dramatic heroics in Sydney.
Wilkinson actually showed no sign of the fractured shoulder facet that delayed his comeback by a fortnight as he kicked the Falcons into a 9-6 interval lead with three crisply-struck penalties.
Northampton, who were without two of their World Cup heroes in Ben Cohen and Matt Dawson, kept in touch with penalties from Shane Drahm and Reihana and they went in front for the first time four minutes into the second half when skipper John Leslie took Drahm's well-timed pass to finish off a period of sustained pressure with the first try of the match.
Drahm's successful conversion made it 13-9 and the visitors then brought on England hooker Steve Thompson to give them more impetus. Newcastle's plight looked increasingly desperate when Wilkinson went off but they regained the lead with two tries in three minutes to turn the game on its head.
First ever-dangerous winger Michael Stephenson, who came up with two breaks in the first half, followed up a kick from hooker Matt Thompson to secure the vital touch, despite vehement claims by winger John Clark that he made the ball dead.
Walder landed the conversion and then came up with an 80-metre interception try to put the Falcons in sight of the winning line. His second goal made it 23-13 but two late penalties from replacement fly-half Paul Grayson kept the outcome in the balance right to the end.