The victory came courtesy of goals from Matty Williams - his first for the club - and another Chris Palmer special, coming after Paul Bolland had been sent off for a two-footed challenge.
Caretaker player-boss Ian Richardson made three changes from last week's 1-0 defeat at Bury.
Mike Whitlow came back to skipper the side, and he replaced the player-boss, who was still struggling with a knee injury. Fit again Rob Ullathorne had to settle for a place on the bench as Richo stuck with a 3-5-2 formation.
The first half of this relegation six-pointer was a surprisingly lively affair, with the game far more open then recent encounters we've seen at Meadow Lane.
Cambridge had the best of the early stages, and they really should have taken the lead with just 3 minutes on the clock. Striker John Turner slid in unmarked to meet a cross from the right but could only guide his effort narrowly wide of the post.
Notts were giving as good as they got, though, but with the visitors looking extremely dangerous on the break it was anyone's guess as to who would open the scoring.
The home side were struggling to convert possession into goals - despite some superb passes from Stefan Oakes - while Cambridge should've taken the lead on at least one occasion.
Visiting midfielder Luke Gutteridge badly scuffed a left-footed effort wide, while Deeney saved a powerful Turner effort.
David Pipe then had the Magpies first real chance, hitting a well-struck shot on 23 minutes that goalkeeper Lewis Price just managed to tip over the crossbar.
First, he appeared to handle outside the area as he struggled to hold onto a long ball under pressure from Gavin Gordon. The linesman failed to flag for that, but after the keeper finally lost control of the ball his desperate lunge brought Gordon down for a cast-iron penalty.
To everyone's surprise, though, Julian Baudet missed his first penalty since arriving here, hitting the spot-kick weakly, and providing a fairly comfortable save for Price.
Notts weren't to be denied, though, and a little under 10 minutes they were infront. Chris Palmer delivered a free-kick that wasn't properly cleared, Gordon headed into the dangerzone and none other than Matty Williams was on hand to bravely dive in and head home his long-awaited first Notts goal.
Commeth the hour, Commeth Matty Williams!
Richo's men finished the first half playing their best football of the game so far, but still looked nervy when the visitors hit them on the break.
The referee then brought an end to an entertaining first half, with the home side perhaps feeling slightly fortunate to be in-front.
Half time: Notts County 1-0 Cambridge United
Notts started the second half sluggishly, with Cambridge taking the game to the Magpies.
Deeney made a decent save from Turner, but could do nothing as John Tudor equalised for the visitors on 53 minutes.
The home side lost possession in midfield and the ball was shifted right to the lively Tudor, who turned Mike Whitlow inside-out before firing in a crackng finish from the 18-yard line for a quite brilliant goal that was no more than the visitors deserved.
Notts had gone backwards after a decent first half display, and it took some excellent defending - with Baudet in particular prominent - to keep Cambridge at bay.
McFaul again showed signs of promise, but does have tendancy to drift in and out of games. His improvement is there for all to see, though and full credit must go to Richardson for having faith in the youngster.
Things took a major turn for the worse on 66 minutes. Bolland stupidly lunged into a two-footed tackle on Stuart Bimson that produced a straight red from referee Trevor Parks.
It seemed a strange decision from my view in the JS stand, and Parks received a fair bit of abuse for his trouble, but having seen the incident on TV it was a certain sending off and Parks got the decision spot on. In fact, the tackle was so bad that Richo might consider fining Bolland for his troubles.
The caretaker Notts boss immediately withdrew the excellent Williams, bringing on Matt Gill in his place in what seemed to be an attempt to hold what we had.
As is often the case though, having 10 men proved more of a help than a hinderence, and Cambridge, who had been all over Notts throughout the second half, failed to muster up another real chance after the sending off.
Oakes went up to play just behind Gordon, and looked to be enjoying his new role when he riffled an excellent effort just wide of Price's left-hand upright.
Gill played in Pipe down the right, the Welsh under-21 captain fired in a deep cross, Gordon just managed to connect with a flick-on that found the ex-Derby man.
Palmer steadied himself and, from a seemingly impossible angle, found the corner of the net with an unstoppable left-footed drive. Price never moved.
The goal was all the more special as Palmer had been enduring arugably his worst display at Meadow Lane this season.
Richardson brought on Ullathorne in place of McFaul to shore things up in the middle, while also bringing on Chris O'Grady in-place of the tiring Gordon. Gordon received predictable abuse from his supposed own supporters, but produced an outstanding display. For a targetman, you could ask for little more.
Notts fairly comfortably saw out the final stages, despite a blistering strike from Fuller that was well held by Deeney, who enjoyed a something of a return to form.
Full Time: Notts County 2-1 Cambridge Utd
Well, say what you like about Richo, but the results are there for all to see: That's 3 wins in 3 games at Meadow Lane under the caretaker boss.
The concerns are still there - this was a scarcely deserved win - but the efforts of the players are far greater then the days under Mills.
Richardson certainly got his team selection, and substitutions, spot on and the defence looks far tighter since he's been at the helm. Now just one point behind the struggling Stags, Notts can perhaps look up the table, rather than down, for the first time this season.
With players like Palmer in the team...anything's possible.
Match Ratings to follow.