Leicester have now won three of their four games in the Gallagher Premiership under Australian Cheika, who was back in the stands after being suspended for their victory at Newcastle last week.
A raucous Leicester home crowd was fired up by a fourth-minute try from Freddie Steward as well as some determined defence as champions Northampton were thwarted in attack time and again.
Cheika said: "I actually have the coach of Richmond AFL here visiting.
"It's his first game of rugby live and he said to me after the game, 'What about the atmosphere?'
"It was amazing, what was happening around the intensity that it builds and I think we really wanted to try and get our crowd involved early.
"Scoring the try early on helped us to get our crowd in the game, that's a weapon for you at home and you should use it.
"I don't think we used it well enough against Bath in the first (home) game, but now I suppose we're acclimatising to some new things and we're able to get the crowd in the game more.
"I feel like the defence is a good base for us, that will stop you from losing games, you can stay in matches like that and that's a good foundation to have."
Leicester scored the only try of the first half through Steward as they led 10-3 at the break, with Handre Pollard and Fin Smith kicking penalties.
The hosts then powered clear in the second half with tries from Olly Cracknell and Ollie Chessum before Tommy Freeman ran in a last-minute consolation for Northampton.
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