Pep Guardiola's men extended their lead at the top of the Bundesliga to 19 points on Sunday, stretching their unbeaten run in the German top flight to 47 games.
Thomas Muller bagged a brace for the Bavarian giants, while Thiago Alcantara and Mario Mandzukic were also on the scoresheet.
Full-back Lahm stressed that Bayern were uninterested in defeats for title rivals Bayer Leverkusen and Borussia Dortmund on Saturday, and that the focus was purely on defeating Hannover.
"It's always hard work beating Hannover at home," Lahm is quoted as saying by Bundesliga.com.
"At the end of the match it looks like it was easy, but it's not as simple as that.
"After the games (on Saturday) we had a chance to add to our lead at the top of the Bundesliga. We were determined to do just that and that showed in the way we performed.
"Our aim is to win every game that we play and we're doing that right now. We can't influence what the other teams do, we can only concentrate on ourselves."
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