Derry thumped All-Ireland runners-up Donegal by 1-16 to 0-08 at Owenbeg.
A new-look Donegal side were 1-05 to 0-05 behind at half-time after Emmet McGuckin's 16th-minute goal and the Oak Leaf County pulled away comfortably in the second period.
In Armagh, a huge crowd of 8,436 turned up to watch the hosts face holders Tyrone, leading to a 30-minute delay before throw-in.
A goal from Eugene McVerry put Armagh three up and in the driving seat with eight minutes to play but the visitors responded in impressive fashion, scoring five unanswered points to win by 1-12 to 1-10.
Colm Cavanagh and Ciaran McKeever were both shown red cards after an early incident before Armagh finished with 12 after Finian Moriarty and Aaron Findon were both shown second yellow cards.
Martin Reilly scored two goals, one from the penalty spot, as Cavan beat Down by five at Pairc Esler.
Cavan were 2-04 to 0-06 ahead at the break and though Conor Laverty found the net in the second half, a missed penalty from Paul Devlin proved costly.
Elswhere, Antrim and Fermanagh had too much for their student opposition, Queen's and St Mary's respectively.
Dr McKenna Cup round 1 results
Sunday
Down 1-09 Cavan 2-11
Derry 1-16 Donegal 0-08
Fermanagh 1-13 Queen's 0-09
Antrim 1-07 St Mary's 0-09
Armagh 1-10 Tyrone 1-12
Saturday
Monaghan 0-20 UUJ 2-10
