Wasps boss Dai Young believes the tight nature of the Gallagher Premiership was on show as his side suffered a 35-31 defeat to 13-man Saints at the Ricoh Arena on Sunday.
Young's men roared back from 28-10 during the second half to leave Saints stunned at 31-28 down.
But Chris Boyd's boys had the final say as Taqele Naiyaravoro powered over to ensure they would leave Coventry with a crucial bonus-point success.
Saints remain second in the league standings, 15 points ahead of ninth-placed Wasps.
And Young said: "This just shows how tight this league is.
"Going into it we were two from bottom, they were two from the top, so it shows there's not much in this league.
"This season is going to be like that right through. Most teams can beat each other and if you're slightly off, it doesn't matter who you are, you're going to lose.
"I'm frustrated we didn't win, really pleased we found a way back into the game, disappointed with that 40-60 period has caused us problems.
"We've got to keep working at it.
Saints were 14-10 up at the break thanks to tries from Cobus Reinach and Teimana Harrison.
Further scores from Tom Wood and Reinach early in the second half seemed to put them out of sight at 28-10 ahead, but Wasps bounced back before being denied late on.
"That period after half-time has been a problem for us all season," Young said.
"We conceded 14 points after half-time and then you're chasing the game. That's a characteristic that has hurt us, it's an Achilles heel throughout the season.
"It's something we've talked about but haven't got it right yet.
"If you look at the stats, we're within a score at most half-times, whether that's slightly in front or slightly behind.
"Then the next 20 minutes get away from us and we're chasing the game. It's disappointing that it has happened again.
"The pleasing factor was after going two-and-a-half scores behind we could've folded, but the boys showed some real spirit and some real quality as well to get themselves back in the game and get our noses in front.
"In fairness, we've got to give Northampton some credit - we couldn't get hold of the ball to see the game out.
"A couple of penalties gave them field position then we ended up inside our 22 and they found a way over.
"The big factor was, after we scored, if we'd found a way in the next two or three minutes to get hold of the ball, I think we could've controlled the game.
"But you can't control the game when you haven't got the ball."