Monaghan fought back from eight points down in the second half to stun Tyrone 4-10 to 2-14 in the Ulster MFC final.
Tyrone led 0-7 to 0-1 before Fergal McMahon and Barry McGinn netted for Monaghan but a Conor McKenna goal left Tyrone 1-9 to 2-1 ahead at half-time.
Ruairi McGlone's goal helped Tyrone move 2-14 to 2-6 ahead as the game appeared to be over.
However, McGinn's second goal gave Monaghan hope and McMahon's last-gasp penalty secured the Farney team's win.
Monaghan were claiming their first Ulster minor title since 1945.
As Monaghan produced their intense late pressure, Tyrone captain Ruairi McGlone was sent-off after getting a second yellow card with two minutes of normal time left.
Tyrone were still two points ahead at that stage but Monaghan then were awarded a penalty - correctly it appeared - after a push in the parallelogram and McMahon held his nerve to beat Sean Fox from the spot.
That brought up McMahon's total in the game to 2-5.
For good measure, Donal Meegan added a further Monaghan point in injury-time as Tyrone were left stunned.
The outstanding McKenna was named man of the match after a brilliant individual match but that would have been little consolation for the Red Hand forward.
Despite their defeat, the backdoor system means that Tyrone also remain in the championship.