The Saints trailed by 17 points early in the second half after James Lowe completed his hat-trick, but the home side never scored again and were forced into an awkward final few minutes by the Premier League leaders who never gave up.
Having previously dealt with everything Northampton had thrown at them in a mistake-riddled first-half performance, Leinster suddenly found themselves on the back foot in the final quarter after handing the initiative to the Saints.
“They obviously have quite an aggressive 'D' (defence) so it's difficult to get the ball into the wide channels and when you do get it in there they are quite aggressive in that wide breakdown and try to spoil that, ” That's what England full-back Furbank said.
“There's an element of frustration because we knew this was going to happen.
“We knew we had to play through them and in the first half we didn't take care of the ball well enough and probably tried to force things that weren't really there in the beginning.
“I think we calmed down after the first 20 minutes and created enough chances to score more points than we did.
“We've had a lot of experience with that all season, just look back at Munster, Exeter, those two games we had to come from behind.
“When we scored that try in the corner we definitely felt like we had given ourselves a really good shot.
“To be honest, they were all quite calm messages.
“We talked about getting back into their half and putting the pressure back on them.
“They shut up with 20 minutes to go and gave us a lot of kicks, so it was about securing that and putting our game on the pitch.
“To be honest, I thought we were going to score down the left side, we probably had the wrong people to score.
“We came close and put ourselves in a situation where we could and should have won that game.”
Captain Courtney Lawes said Northampton never believed Leinster, whose out-half Ross Byrne missed a penalty and two conversions, were never out of sight.
“To be honest, I never felt like we were out of the game,” he said.
“In the second half, when they scored that early try, that was one of the points where we had to find ourselves as a team. I thought we did that. It's a credit to the players that we can make something like that happen and find a way to get back on the horse and go at them again.
“Doing that as a team is very good for the future.
“The disappointing thing is that we haven't really tested them. We didn't really play our game the way we wanted to, we dropped a lot of balls and gave away a lot of penalties. If you do things like that, you can't win at the highest level.
“That was obviously the point where we lost the game, but on the plus side we were able to push one of the best teams in the world and show that we're not going to be pushed over by anyone.
“We can learn a lot from it and there are also very good lessons to be learned from it.”