Sinoti Sinoti celebrated his new contract by scoring Newcastle's fourth and final try in a 28-10 win over Harlequins, their first Aviva Premiership victory at the Stoop in almost 18 years.
There was nothing to separate the sides at half-time as an early James Horwill try was cancelled out by Callum Chick at the other end.
But shortly after the restart, Kyle Cooper and Chris Harris went over in quick succession for the visitors before Sinoti followed them over the whitewash, sealing a first league victory in south-west London for the first time since September 2000.
An excellent touch-finder from Marcus Smith led to the game's first try on seven minutes, Horwill barging over at the second time of asking following a good offload by Dave Ward, Smith converting.
With 10 minutes on the clock, both sides were reduced to 10 men as the hosts' James Chisholm and Falcons' Nili Latu were sent to the sin-bin, with the number eights involved in an off-the-ball altercation.
Newcastle then dominated possession in and around Harlequins' five-metre line but despite several attempts to barge over, the home side held firm.
The visitors were fortunate not to fall further behind on 22 minutes when Smith sent a 30-metre penalty in front of the posts wide.
But after Harlequins hooker Joe Gray was sin-binned for collapsing a maul, Newcastle were level as Chick inched over the line following a sixth Falcons line-out, Flood converting.
It was Vereniki Goneva's turn to be held up over the line as Newcastle pressed again but despite being reduced to 14 men once more when Alofa Alofa was sent to the bin following a number of Harlequins infringements, the home side survived.
Despite being a man down, the hosts started the second half on the front foot and Smith put the hosts back ahead with a penalty from 30m in front of the posts.
But Falcons were not behind for long and after Simon Hammersley was held up over the line following a fine Josh Matavesi break, Cooper barrelled his way over.
Flood converted to put Newcastle 14-10 ahead with 30 minutes remaining and moments later the visitors were further ahead as Harris brushed off Luke Wallace to dot down.
Veteran fly-half Flood once again added the extras before being replaced by Joel Hodgson, who made no mistake with his conversion on 66 minutes after Sinoti beat Chisholm one-on-one on the left wing to wrap up Falcons' bonus point.