A fortuitous 54th minute goal from Gearoid McKiernan proved crucial as Cavan came from behind to repeat their Allianz League win over Down in this fiery clash.
The Mourne men recovered from losing key attackers Connaire Harrison and Kevin McKernan to black cards (both in the 30th minute) as well as seeing Caolan Mooney limp off and Ryan Johnston pick up a straight red to edge into a four-point lead with 20 minutes to go.
However, Cavan overhauled them with points from Niall Murray, Ciaran Brady, Oisin Kiernan and McKiernan to seal their place in round three.
There was more drama at the death, too, as a melee erupted in front of the stand and referee Cormac Reilly showed red cards to Cavan’s Dara McVeety and Conor Moynagh and Down’s Anthony Doherty.
The Blues were the better side early on and eased into a 0-3 to 0-1 lead through Sean Johnston (free), Ciaran Brady and McVeety.
Two further Johnston frees and an excellent McKiernan score made it 0-6 to 0-2 but the underdogs dominated the remainder of the first half, with Harrison, Ronan Millar (two frees) and Doherty (free) all on the mark.
Eamonn Burns’s men made light of the losses of Harrison and McKernan to land the final two points of the half from Niall Madine and Sean Dornan as they went in holding a 0-10 to 0-8 lead.
Both sides were set up defensively – Cavan employed three sweepers at times – but Down were that bit slicker up front at this stage and three points in succession from David McKibbin, Millar (free) and Dornan made it 0-13 to 0-9 as the upset seemed on.
However, Cavan were buoyed by their goal – McKiernan’s point attempt dropped short and through the hands of goalkeeper Shane Harrison – and with Down reduced to 14 men following Johnston’s dismissal, Mattie McGleenan’s charges finished strongly to march on.
Late scores from Padraig Faulkner and McKiernan sealed it, with Down’s Darren O’Hagan denied a goal by a good save from James Farrelly in the dying seconds.
Cavan: James Farrelly, Killian Brady, Padraig Faulkner (0-1), Enda Flanagan, Ciaran Brady (0-2), Conor Moynagh, Martin Reilly, Sean McCormack (0-1), Bryan Magee, Oisin Kiernan (0-1), Gearoid McKiernan (1-2), Niall Murray (0-2), Conor Bradley (0-1), Dara McVeety (0-1), Sean Johnston (0-3f)
Sub: Fergal Reilly for K Brady (ht), Cian Mackey for Johnston (42), Caoimhin O’Reilly for Magee (42), Adrian Cole for McCormack (54), Niall Clerkin for Kiernan (65), Jason McLoughlin for Flanagan (70)
Down: Shane Harrison, Ryan McAleenan, Brendan McArdle, Anthony Doherty (0-4f), Darren O’Hagan, Niall McParland, Caolán Mooney, Peter Turley (0-1), Niall Donnelly, Ronan Millar (0-4, 3f), Kevin McKernan (0-1), Conor Maginn (0-1), Sean Dornan (0-2), Connaire Harrison (0-1), Ryan Johnston
Subs: David McKibbin (0-1) for McKernan (BC, 30 mins), Niall Madine for Harrison (BC, 30), Jonny Flynn for Mooney (44), Conor Poland for Donnelly (51)
Ref: Cormac Reilly (Meath)