Downth opened the Robin series campaign throughout Ireland by mitigating the past Claire in Enis, while Cavan was shocked in Klasbar.
Morne County produced a screen in the first half to lead 14 points at the end of the first half before it remained clear to win 17 points in the opening match of the third group.
But Cavan was launched from a great shock in the first group by drowning the qualified in the Connect finals 1-17 to 1-14.
The BreffNi men led 0-9 to 0-7 at the end of the first half with Mayo failure to score from playing to 32 minute before defender David loses near a black card.
Cavan has fully benefited from their numerical advantage in the early half of the second half with 1-3 in the five-year opening minutes, with Gerard Smith scored his team's goal.
The Ulster team kicks the top in the 39th minute and was the advantage that they refused to abandon it.
Cian Madden and Stephen Coen exchanged degrees where Cavan is able to keep their noses in the foreground.
Aidan O'Shea hit the network for the host team with the last measure of the game, but the Raymond Galligan team won the three -point shock victory over the first group.
CAVAN CHAVIONS DONEGAL will host in two weeks while Mayo will travel to omagh to take over Tyrone looking to get their first points.
Meanwhile, Down to the start of a flight in Ennis, where it rose to 1-3 to 0-0 after five minutes with John McGo fired on the network.
Danny Magil kicked six degrees in the first half, reducing the Conor Laverty team.
They led 2-12 to 0-5 three minutes before the break when Daniel Guinness was raised to raise the green flag.
Two minutes later, Aaron Griffin hit the net to the competitors on the monster, but they crossed 2-17 to 1-6 in the interval.
In the second half, it was the Ulster team that held a company, adding a third goal through Caolan Mooney. Pat Haveren kept the results plate beating, as well, where he ended nine points.
After they started their campaign elegantly, Downton will welcome Lingter Loth, for his presence in two weeks.
