A second-half goal from Jack Haughey helped Down to a 1-11 to 1-8 victory over Fermanagh in Sunday's Ulster MFC quarter-final at Brewster Park.
The Mourne team held a 0-4 to 0-2 lead at the break and moved four points ahead early in the second half.
Fermanagh hit back with a 43rd minute goal from substitute Thomas McCaffrey.
Haughey slid in Down's goal six minutes later and the visitors went on to win by three points to set up a semi-final clash against Monaghan.
Fermanagh: P Sweeney, S O'Hara, N McMahon, C Corrigan, P Coalter (0-2), P Leonard, M Beagan, J Allen, N Shannon, L Jones, E Courtney (0-5, 3f), C Murphy, C Logan, S Keenan, E McManus (0-1). Subs: T McCaffrey (1-0) for Jones, N Carson for Logan, G McManus for Allen
Down: R Burns, A McDonald, A Doherty, M O'Hare, D McKeever (0-1), R Wells, J McDermott (0-1), D Doyle (0-2), D McCarthy, C Gallagher, S McGonigle (0-1), R McAlinden, J Haughey (1-2), T Grimley (0-1), C McGrady (0-1). Subs: D McAleenan (0-1) for McGrady, P O'Hgaan for McGonigle, D McKeown (0-1) for Gallagher
Referee: S Hurson (Tyrone).