Waller: We had a point to prove
Irish had yet to win in the Premiership this season before last Saturday's 25-23 win over Saints.
And with just three victories from their opening seven matches in the league during the 2015/16 campaign, last season's table-toppers knew improvements were needed.
It came courtesy of Mike Haywood's try and JJ Hanrahan's penalty in the first half, with Gareth Steenson's late kick securing the visitors a losing bonus point at Franklin's Gardens after an improved second-half display from Rob Baxter's men.
"It was massively important that we won this week," Waller said.
"We had a few upfront chats in the week about how we performed last week and it wasn't good enough.
"It was a great reaction from the lads. We worked hard in training to put it right because we knew we could play better than we did last week.
"Exeter put up a great fight but the boys had a point to prove and we proved that today."
He continued: "I think we let ourselves down a bit defensively last week with our discipline and that was a massive focus for us.
"But we showed before that against Racing 92 that we can front up and we had to find that form this week.
"It was something that we talked about this week and defensively we worked hard on it and it was nice to see that when we work on something it shows. But we need to keep that consistency now."
Exeter head coach Rob Baxter meanwhile admitted to having mixed emotions.
Baxter was disappointed with the performance which he believed lacked intensity but was also pleased to leave with a losing bonus point.
He said: "The truth is I think we've stolen a bonus point from today if I'm honest.
"Almost from the first quarter of the game, you could tell I don't think we had the intensity about us which was to come here and demand a win or force enough moments in the game for us to be able to win.
"To be in the situation where we've got the last possession of the game and be in with a chance of winning it, I think shows a lot about their character.
"But I have said to them that wasn't a performance that was going to win them the game and that's the truth.
"Northampton looked more comfortable, and they had longer periods of territory and possession.
"Away from home we have to make things happen and if you look at today, when we got territory we didn't create a driving game which was strong enough or good enough.
"Those little bits of accuracy and intensity were lacking today. If they'd been there, I think we'd have got more out of the game because I'd like to think we can always score more than eight points.
"Almost tougher than losing the game is probably the fact we only scored three points."
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