Tyrone recovered from two early Monaghan goals to run out 0-17 to 2-8 winners in their Ulster Under-20 quarter-final at Healy Park.
Paul Donaghy hit five points as Tyrone battled back to reach the semi-finals.
Armagh knocked out Fermanagh to secure their place in the last four with a 2-14 to 0-10 success in Enniskillen.
Goals from Rian O'Neill and Conor Turbit helped Armagh to a comfortable victory against an injury-ravaged Erne county.
Monaghan raced into an early lead against Tyrone as Dean McDonnell and Oran McElligot both had the ball in the net inside the opening five minutes as the visitors threatened to repeat the Senior team's triumph on Sunday.
Donaghy knocked over three points for the Red Hands and Cahir Goodwin was also on target but Monaghan led by 2-4 to 0-5 at half-time.
Tyrone had wind advantage in the second half and set about chipping away at the deficit with Matthew McGleenan sending over a couple of scores.
Emmet McNabb added two stylish points before substitute Tiernan Drayne edged them in front for the first time in the 51st minute.
Drayne made a big impact with two more scores before Donaghy brought his tally to five as Tyrone set up a semi-final clash against Armagh.
Fermanagh also led early on in the night's other quarter final before O'Neill's goal gave the Orchard county a 1-3 to 0-4 advantage.
After going in 1-5 to 0-5 ahead at the interval, Turbit's goal increased Armagh's lead to seven points.
With Fermanagh losing Lorcan McStravick, top-scorer Callum Jones and Johnny Cassidy to injury, Armagh extended their lead in the closing stages to advance to the last four.