Northampton director of rugby Phil Dowson admitted his side “let Newcastle in” at times during their 36-19 Gallagher Prem victory at Kingston Park.
A positive start saw JJ van der Mescht and Alex Mitchell score for Saints before Oli Spencer and Amanaki Mafi responded either side of a Van der Mescht yellow card.
Tommy Freeman scored on the stroke of half-time for the visitors but they were handed another blow when Van der Mescht was shown a second yellow, resulting in a 20-minute red card at the start of the second half.
Stefan Coetzee pulled one back for Newcastle but Saints saw the game out when Edoardo Todaro and Alex Coles crossed either side of Fin Smith’s penalty.
Newcastle entered the game on the back of a bruising 57-5 defeat to Sale last weekend and Dowson knew his side would face a tough test at Kingston Park.
He said: “I sat this time last week watching Sale against Newcastle and I was a little bit frustrated because I knew there’d be a huge reaction from Newcastle this week.
“Lots of players who are finding their feet in the Newcastle system and I knew they’d be so much better this week and have a real point to prove.
“I thought we started very well, but there’s lots of very good players in that Newcastle side.
Match Summary 
“We struggled to put our game together for long periods of time and our discipline was poor, which let them in.”
Asked for his thoughts on Van der Mescht’s red card, Dowson added: “If they make those decisions that technically JJ was cynical and a yellow card in the first half for a lineout offence, then if (the second) was deemed a high tackle, then they’re well within their rights to do that.
“My concern was they spent a lot of time checking that and didn’t check a tip tackle on Tommy Freeman, or did they? It’s hard to know from a communication point of view.
“I’m very happy for people to check and TMO to come in, for things to be looked after from a safety point of view. But if you’re going to check that, you have to check everything.”
Newcastle slipped to their fourth defeat of the campaign, leaving them at the foot of the table.
Boeta Chamberlain’s game-levelling try was disallowed before Saints stormed ahead, but head coach Alan Dickens believes it was a more “positive” display than last week’s defeat.
He said: “We saw today it was a much better performance. Being picky, the try right on half-time was disappointing to concede that.
“Again, the character and the way that the lads stuck together for 80 minutes was a positive against a team that lost in the Champions Cup last season.
“We’ve talked about cohesion in the last few weeks, they’re a team who’ve been together seven, eight years.
“I think it was documented in the week, we talked about the kind of Northampton model – building from within, building from the academy, it’s something we’re looking to do here.”