Chris Boyd admits Saints were made to pay for some 'sloppy execution' as they suffered a frustrating 22-13 defeat at Bath on Saturday afternoon.
The black, green and gold charged into an 8-0 lead inside the opening 10 minutes thanks to Rory Hutchinson's try and James Grayson's penalty.
But Bath battled back, making the most of Saints' indiscipline to lead 10-8 at the break, despite having been on the back foot for long periods.
Boyd's side continued to push on in the second period as they looked to get their lead back, but a red card for Bath wing Aled Brew altered the pattern of the game.
It wasn't in Saints' favour as they soon shipped a try to Will Stuart before Tom Wood responded.
The Bath pack had the momentum though, and their scrum sunk Saints as they conceded again following yellow cards for Ben Franks and Paul Hill.
And Boyd said: "We probably created enough in the first half to have a few more points on the board, but we were a bit sloppy with our execution so didn't get that buffer.
"We lost 15 minutes of the game with a succession of scrums and yellow cards and it ultimately sunk us so it's a bit disappointing really.
"It's one way for them to win a game and credit to Bath for coming away with the victory and the points.
"We're disappointed to come away with nothing and we always knew it was going to be an arm wrestle.
"We just showed a bit of inconsistency in our execution and it was a tough place to play for us.
"Some of the stuff we put out there the boys felt was as good as we had technically executed, but our last pass just went astray and it slid away from us.
"That last little bit didn't go our way at all."
Saints had won all three of their Gallagher Premiership games this season prior to their trip to The Rec.
But when asked about how his side's scrum functioned late on, Boyd said: "On our ball we're sitting at 96 per cent clearance so we don't have any problem with our own scrum.
"As you could see, Bath wanted to scrum for penalties and we've got to learn to bite our mouth guard and hold in because their game plan was to scrum for penalties.
"It was going okay and then I wasn't 100 per cent sure why Ben Franks was yellow carded.
"The Ben Franks yellow card forced us to bring young Toby Trinder into the game for what was his first ever Premiership game, a really big ask for him.
"Paul Hill then conceded a yellow card in the melee and to be quite honest, I wish the referee had just given a penalty try at the start and we'd have had 12 minutes to try to chase the game.
"But not only did we concede the try, it took an awful long time to do it."
Brew's red card came for a forearm smash on George Furbank, leaving the home fans furious and firing up the home team.
Asked whether he felt it was a fair decision from referee Ian Tempest, Boyd said: "It's really tough and it's not the referee's problem. The problem is the criteria they now place on what the process is for that.
"If they see it's a forearm to the neck or head then under the process they go through, they've got no choice but to give a red card.
"Most rugby people would think it was a little bit harsh and I don't think there was any intent or malice there, but the way they rule the rule is that if there's a blow to the neck or head, that's the process.
"I felt sorry for the kid because I didn't think there was any malice in it but that is not part of the judgement of the card system."