Keith Higgins struck a late injury-time goal as Mayo defeated Donegal 2-14 to 0-17 in the pair's Nicky Rackard opener in Letterkenny.
Despite Adrian Phillips first half goal for the away side, Donegal still seemed to be in control for most of the contest, Declan Coulter leading the way with 0-09.
When Coulter pointed in the final minutes of normal time to make it 0-17 to 1-10, the hosts appeared to have done enough.
But then Higgins, a four-time football all-star, notched a point before levelling things with a scrappy goal after Donegal failed to clear their lines. With the game now in injury-time, Mayo attacker Shane Boland wrested control of the contest, landing three late points to give the Connacht side victory.
Longford hammered Louth by 20 points in the pair's Lory Meaghar Cup opener in Glennon Brothers Pearse Park this afternoon.
The hosts had six goals lashed home in the opening half with Cathal Mullane, David Buckley and a Rueben Murray hat-trick, plus an own-goal leaving the score at 6-09 to 1-13 at the break, David Kettle finding the net for the visitors.
Further goals from Stephen Creavan and Joe O'Brien saw them run out 8-24 to 3-19 winners.
