at Páirc Tailteann
An astonishing final half hour from Cavan, during which they out-scored Meath by 1-15 to 0-4, was the difference as the Blues picked up their first points in this year's Division 2 campaign.
Buoyed by a well-taken 22nd minute goal from speedster Eamon Wallace, the Royals went in at the break 1-9 to 0-5 ahead, although the Breffni men had kicked eight wides and saw a Seanie Johnston effort thunder off the underside of the crossbar.
But when Sean Tobin pointed early in the second half, it looked as if Mick O'Dowd's men would rompt to an easy win.
Cavan had other ideas, though, and with Killian Clarke putting the shackles on the hosts' danger man Graham Reilly, David Givney relocated on the edge of the square and Johnston using the ball cleverly, they tore into their opponents.
Johnston, who finished with 0-6 on his first competitive start since 2012, began the comeback and when Givney tucked away a goal in the 45th minute, Meath were suddenly asked a big question – and they couldn't find the answer.
Two inspirational scores from centre-back Conor Moynagh helped Cavan edge in front, with sub Niall Murray kicking two from play.
The famed Royal resilience was nowhere to be seen as Cavan ran through at will in the last 10 minutes, sub Paul O'Connor and midfielder Tomas Corr also firing over as the most implausible of comebacks became a reality.
Meath lost goalkeeper Paddy O'Rourke to a straight red card in injury time but by that stage it mattered little as their neighbours enjoyed a win which keeps alive faint hopes of promotion.
Cavan had so many heroes in the second half. Dara McVeety was awesome, Killian Clarke and Sean Johnston everywhere and Moynagh and Brady at the back were tremendous.
Cavan: R Galligan (0-01, 0-01f); P Faulkner, K Clarke, J McLoughlin (0-01); G McKiernan (0-02), C Moynagh (0-02), C Brady; T Corr (0-01), F Flanagan; D McVeety (0-03), D Givney (1-00), M Reilly; C Mackey, M Argue (0-01), S Johnston (0-06, 0-02f).
Subs: N Murray (0-02) for Flanagan, K Brady for Reilly, P O'Connor (0-01) for Mackey, J Brady for Johnston, L Murphy for McLoughlin, B Sankey for McKiernan.
Meath: P O'Rourke; B Power, C McGill, D Keogan; D Smyth, P Harnan, M Burke; H Rooney, G Reilly (0-02); E Wallace (1-03), C O'Sullivan, D Tobin (0-01); S Tobin (0-03, 0-02f), M Newman (0-04, 0-03f), D Lenihan.
Subs: C Finn for Smyth, J O'Reilly for Finn, A Tormey for Power, M Battersby for O'Sullivan.
Referee: R Hickey (Clare).