When Lancaster stepped into the middle of the wreckage that was English rugby on December 8 last year, few could have envisaged a result or a performance like it.
Even on Saturday morning, it was a stretch given that the All Blacks were on a 20-Test unbeaten run and England were reeling from successive defeats to Australia and South Africa.
But Lancaster's callow team delivered one of the great England displays. The All Blacks, who some have called the best team ever, could not live with the thunderous intensity. Owen Farrell kicked England into a 15-0 lead before their character was tested when New Zealand hit back with two converted tries in three minutes.
England's response was emphatic. Brad Barritt, Chris Ashton and Manu Tuilagi scored in quick succession before Freddie Burns came off the bench to kick two penalties on his debut.
While deservedly proud, Lancaster also stressed the need for England to use this victory as a launchpad for the RBS 6 Nations and to the 2015 Rugby World Cup.
"It's the highest point, isn't it? We've played the world champions, who were unbeaten in 20 matches, and we've put in a performance that has beaten them fair and square," Lancaster said.
"To put in that type of performance under that sort of pressure after the scrutiny of the last two weeks, is fantastic, really.
"It was less than 11 months ago we changed the direction of travel for England rugby, to build a team for the future but wanting to win in the here and now.
"Sometimes it takes a win to show that and the most pleasing thing is it has given a clear view of the direction we are going. We've got to make sure we hit that level in the Six Nations."
Lancaster took the decision, initially as interim head coach, to cut adrift the experienced players who had failed at the World Cup and rebuild the England side.
Seven of the starting team that beat New Zealand were only capped this year. Chris Robshaw had made just one previous England appearance when he was named captain before the Six Nations.
The new band of brothers went on to finish second in the championship, beating France in Paris and then Ireland at home. It was a glorious honeymoon, though reality began to sink in during the summer tour of South Africa, when the Springboks won the first two Tests before England rallied to draw the third.
Back on home soil in the autumn, England were shown up as naive in the 20-14 defeat to Australia and were then edged out 16-15 by South Africa in a game they should have won.
But equally there is much to be excited about.
"I've never doubted the direction we're going," added Lancaster.
"Rugby's fairly simple. If you get a good culture, a good environment, good players, good coaches and if you work hard enough, you'll get results.
"I believe in the players we've got like Joe Launchbury, Jonathan Joseph and Owen Farrell and Freddie Burns who are 21, 22 and 23 years old.
"They should be playing for England for years and we should be sat here in 10 years' time and still have the same group of lads with 800 caps [instead of 206] in our starting XV.
"And we've got good players to come back into the equation for the Six Nations, such as Dylan Hartley, Tom Croft and Ben Foden.
"The 15-0 half-time score was fantastic. To get that scalp is a fantastic scalp."