The 19-year-old, who started the season on loan at Bedford, kicked 17 points and played with an authority that belied his age as Saracens beat the Tigers 22-18 to lift their first league crown.
Farrell will end his breakthrough year playing at the Junior World Cup in Italy, but he wants to follow his father, Andy, into the senior England team.
"I'd love to get an England jersey on my back now," said Farrell junior. "I have always been a person with big aspirations and I have always been confident I could take my chance but you never know until you are out there.
"To come to a special place like Twickenham and do that to Leicester is unbelievable. Dad was very excited afterwards.
"This year I think I have surprised myself as well as surprising other people. I have still got a hell of a lot to learn."
Farrell was recalled from Championship club Bedford in November after Derick Hougaard was sidelined by injury and Farrell played a pivotal role in Saracens' 13-game winning run to the title.
A year out of school and playing the biggest game of his life, he was coolness personified at Twickenham, while the more experienced Flood struggled to impose his authority. He missed two simple kicks, where Farrell was faultless with the boot.
There was a significant moment in the closing stages, as Saracens mounted a goal-line stand to protect their lead, when Farrell dumped Flood on his back-side.
The official man of the match award went to Saracens hooker Schalk Brits, but he reserved praise for Farrell's contribution.
"Owen Farrell is a kid who played like a man. For a kid of 19 to play rugby like that is a phenomenal feat. He'll definitely play international rugby."
Farrell's more immediate challenge will be to keep hold of the Saracens 10 jersey, with Charlie Hodgson bound for Vicarage Road next season while Hougaard has signed a new deal.
"We play a rotation at our club. Charlie is experienced, and I hope to learn a lot from him but hopefully I can play enough games to carry on learning and improving," said Farrell.
"We have created something special and this is the start of it. We want to go for in the Heineken Cup and we want to be here every year."
Scorers: Leicester: Pens: Flood 6. Saracens: Try: Short. Con: Farrell 3. Pens: Farrell 5.
Leicester: Hamilton, Agulla, Smith, Allen, A. Tuilagi, Flood, Youngs, Ayerza, Chuter, Castrogiovanni, Mafi, Skivington, Croft, Newby, Crane. Replacements: Twelvetrees for Hamilton (75), Stankovich for Ayerza (78), Hawkins for Chuter (68), Cole for Castrogiovanni (53), Slater for Mafi (71), Waldrom for Crane (50). Not Used: Grindal, Staunton.Saracens: Goode, Strettle, Wyles, Barritt, Short, Farrell, de Kock, Stevens, Brits, Nieto, Borthwick, Botha, K. Brown, Burger, Joubert. Replacements: Wigglesworth for de Kock (50), Gill for Stevens (62), Du Plessis for Nieto (60), Vyvyan for Botha (57). Not Used: George, Saull, Mordt, Cato.
Referee: W Barnes. Attendance: 80,016.