Scott Burgess and Caleb Russ provided a threat up top, with the ball being worked well into wide areas quickly and delivered into the box.
Despite fashioning a number of openings in the first half, both teams went into the sheds level. The second half started in the same way as the first, and Burgess could only find the crossbar after beating the keeper with a fine effort when through on goal.
The hosts paid the ultimate price for their profligacy in the 80th minute when Cambridge countered and struck a killer blow- Josh Clarkin finishing past Shane Stanners, although there was more than a hint of handball in his first touch.
Jamie Woodlock sealed the result five minutes later as Northland threw bodies forward, and it probably sees the reds into the Northern League for 2019.
Head coach Dan Johnston said: "We asked the boys for a reaction after last week and you could see in training that they were ready. I thought we took the game to them and got our tactics right but unfortunately the result didn't go our way. This season is going all the way to the wire and we have to stay positive because we aren't out of it yet."
Northland are on the road for the final time this year against Onehunga Mangere next week.