Newman had pleaded with the supporters in the build-up to the match to have patience, but it was wearing wafer thin even among the ultra faithful and ultimately with club chairman Lee Power as United folded in a feeble second half.
The fans left the Abbey Stadium chanting "Newman Out" and after half and hour or so, Power instead of the manager came to the press conference, where he announced that Newman and his assistant Tony Spearing had been sacked.
Newman had hoped to kickstart his team's stuttering campaign by making seven changes from the side beaten 2-0 at Dagenham last weekend, but his plans unravelled alarmingly as the match wore on.
Centre-back Mark Peters scored a controversial goal for the home side in the 21st minute, but inspired by the lively Lee Phillips Exeter stormed back to take complete control.
The statistics surrounding the match were particularly damning for the beleaguered manager. It is the worst start to a season for 42 years by a Cambridge side, whereas the victory at The Abbey was a first for Exeter in 20 visits, a sequence stretching back and astonishing 30 years.
They had an unexpected helping hand midway through the first half when a whistle was blown among the supporters behind the Exeter goal while a free-kick was being taken.
As the City defenders momentarily took their eye off the ball, Peters blasted a header under the crossbar from Jon Brady's kick.
At that stage it looked as thought the Cambridge might be building the kind of momentum which might leave them to their first victory of the season.
They were unable to follow up the goal as the Grecians gradually fought their way back into the game. A series of corners around the 35 minute mark for the visitors seemed to be the turning point and it was no real surprise four minutes before the break when Phillips crashed a shot in off the crossbar after an excellent run from Jamie Mackie.
Exeter got off to a flying start after the break, pinning Cambridge back and exposing all the faults in a defence which had always been struggling in previous matches this season.
Exeter took the lead in the 55th minute with a superb goal as Phillips burst between two defenders, held off a challenge as he chipped a pinpoint pass into the path of Jon Challinor, who ran in unopposed to stab the ball between the keeper and the post.
There was one solitary moment where it looked as though Cambridge might get back into the game, Brady rattling the angle of the post and crossbar with a 30-yarder on the hour.
But it was as good as over for the East Anglians just four minutes later when they allowed Exeter to score an embarrassingly easy third.
As two replacement forwards were waiting to go on for Cambridge, Phillips virtually strolled through the shambles of a defence on the right and hit a cross-cum-shot which was pushed into his own net by goalkeeper Paul Crichton.
That was when the anti-Newman chant built into an angry roar, seeming to inspire Exeter to dominate even more completely.
It could have been an even more embarrassing final match for Newman and his assistant, but Exeter squandered several opportunities in the dying minutes.