The world champions extended their unbeaten record to 20 Tests against all opponents and inflicted a 25th successive defeat on Wales, stretching back 59 years.
Hansen said: "We put them under a lot of pressure but then of course got Cory (Jones) in the sin-bin (for a deliberate knock-on) and we lost our control and shape for some time - which allowed them to come running back at us.
"But we can't afford to get ahead of ourselves and if we don't prepare in genuine fashion England will give us a thumping next week.
"However, we'll enjoy this success and start again on Monday."
Hansen had little to say about the incident which saw All Blacks hooker Andrew Hore punch lock Bradley Davies from behind.
Although the New Zealand player escaped censure from erratic match referee Craig Joubert, citing commissioner Mike Rafter is likely to take a different view.
Hansen said: "I haven't seen it so I'm not going to get too carried away - but I saw him hooking Bradley Davies out of the way. How he did it we'll have to look at on the video."
Wales coach Warren Gatland added on BBC2: "We could have thrown in the towel against the world champions but we didn't do that.
"I thought we grew into the game and took the game to them in the second half. I'm proud of the way we stole territory and possession in the second half but unfortunately we weren't able to do it in the first and the game got away from us.
"We wanted to take the game to the All Blacks. You've got to take some risks against them."
On the Hore/Davies incident, Gatland added: "It was disappointing to lose Bradley and I thought it was a little bit of off-the-ball stuff."