United looked set to have to settle for a draw after Sasa Lukic had cancelled out Jacob Murphy's first half opener.
But Eddie Howe's substitutes made the difference.
Sandro Tonali wrestled back control for the Magpies and fellow substitute Will Osula forced a fine save from Bernd Leno giving Bruno the chance to turn in the rebound.
Here are the main talking points from the game:
**THE CHANT AT FULL-TIME**
--------------------------
He's still having to settle for a place on the bench but Osula is playing a much more prominent role for Newcastle this season.
The striker has featured in every single Premier League game and it was the 22-year-old's direct late run and shot that resulted in Bruno's tap-in and gave the Magpies a much-needed victory.
His contribution was certainly recognised, for it was Osula's name being chanted in stoppage time and several players in black and white rushed to congratulate the striker at full-time.
Osula is still clearly very much a work in progress but the striker who very nearly left on deadline day has shown that he can be a crucial squad figure this season.
UP AND DOWN FIRST HALF
----------------------
When the ball went out for a throw-in down near the dugouts after five minutes, Howe darted over and got it back to Dan Burn in an instant. Newcastle were in a team in a hurry.
They’d already hit the post through Nick Woltemade after three minutes and gone close through Bruno after four. And from the throw-in on the left came an opportunity down the right, Jacob Murphy going for goal from a tight angle and the post denying the Magpies for a second time.
Marco Silva looked understandably frustrated but that was nothing compared to his irritation when Newcastle got themselves in front on 18 minutes, with the visiting boss no doubt furious for two reasons.
Firstly, his side looked to have weathered the early storm and wrestled back some control. Indeed, they could have taken the lead themselves when Ryan Sessegnon found Raul Jimenez in the box and the striker created space for himself but missed the target.
Secondly, Newcastle’s opener was a gift, Calvin Bassey caught napping by Murphy, who raced away and kept his cool to find the bottom corner with a fine finish.
It was not, however, a springboard. At least not in the first half. Newcastle continued to be too sloppy in possession and Fulham’s best chances came from the home side’s poor play. Sasa Lukic should have done better from the edge of the box after Sven Botman cheaply conceded possession on the stroke of half-time.
Earlier, Sander Berge had forced a save out of Nick Pope before Adama Traore fired just wide.
FEARS OF A REPEAT
-----------------
It was Murphy who fired Newcastle into a 1-0 lead at home to Fulham back in February, only for the Cottagers to roar back in the second half and take all three points.
The Magpies were fearing a repeat when Sasa Lukic bundled in the leveller 11 minutes into the second half. It was the least Fulham deserved, for the visitors had been the better team just before Newcastle’s opener, responded well to falling behind and were bright and dangerous after the interval.
Silva was also rewarded for his half-time substitute. Kevin was introduced in place of the anonymous Emile Smith-Rowe and the Brazilian made a big impact, troubling Trippier and delivering the cross that led to the equaliser.
THE GAME-CHANGER
----------------
The moment Fulham’s goal went in, Howe turned and signalled instant changes. One was forced, with Botman unable to continue and replaced by Fabian Schar, but midweek scorer Barnes and Tonali – to the delight of the home fans who were singing his name – was also introduced.
Tonali, in particular, was needed as Newcastle craved composure and control. And the midfielder was the game-changer. He just settled everything down and provided 20-odd minutes of evidence, not that it was needed, of how Newcastle are just such a better team with the Italian patrolling in the middle of the park.
HOWE'S WISH
-----------
It was this time last week that Howe admitted Newcastle’s over-reliance on Nick Woltemade’s goals was a concern.
It will come as a relief, then, that three of the four goals scored since have come from United’s wide players before Bruno's last gasp winner here.
After Gordon’s opener against Benfica on Tuesday and Harvey Barnes’ brace from the bench, Murphy got off the mark for the season with his breakthrough on Saturday.
It’s a step in the right direction but this was by no means Newcastle at their best in an attacking sense and there's much more to come.
When Gordon got right-back Kenny Tete booked after just two minutes, it looked nicely set-up for the winger to build on his Benfica display, after which Jose Mourinho told him he was “too much”. But it turned into a frustrating afternoon for the England international and he was replaced for the final quarter of an hour by Anthony Elanga.
But Gordon dived out of the dugout to celebrate with Howe and Jason Tindall after Bruno's late heroics.