Flood clinched the 31-29 victory by booting a 50-metre penalty in the final minute, denying Leicester top spot after leaders Bristol saw their scheduled appointment with Northampton postponed.
The 21-year-old also added a try, two conversions and three earlier penalties - leaving Falcons rugby director John Fletcher purring about the twice-capped Flood's Six Nations prospects.
Fletcher said: "Toby has to be in with a shout when it comes to being in the England team or the squad for the Six Nations.
"Given the other contenders, he has to have a real chance - and he will be able to handle it. He has two international caps and approaching something like 50 appearances in the Premiership.
"He's also pretty level-headed and knows what he is about."
Flood revealed his last-gasp heroics were achieved in new boots.
"My boots cracked during the week, so I had to get some more on Saturday," he said.
"Most players don't like playing in a pair of boots they haven't worn before. But I didn't really have much choice - because my other ones were trashed, so I just gave them a go and thankfully the result went our way."