Mournemen are left Down and out after Celtic Park loss
Derry0-11 - 0-10 Down
Even though the pattern of the game and the key performance indicators fell in their favour, Derry were forced into an almost insufferable sweat to fall over the line against a Down side that nipped at their heels all the way here at Celtic Park.
When they went in at half-time their briefing had to be positive and to continue doing what they had been doing, leading them to be 0-8 to 0-5 up.
Down had tried Conaill McGovern as a sweeper to double-team Eoin Bradley along with Darren O'Hagan, but soon rotated Ryan Boyle onto the role, such was the panic the Glenullin man's power and speed spread into the Down defence.
Derry's totemic midfielder Fergal Doherty had made four clean catches from kickouts, while also hoovering up some breakball with Sean Leo McGoldrick. After three early wides, captain Mark Lynch produced a tour de force with four first half points.
At the other end, they had limited Down to two scores from play, both coming from spectacular Kevin McKernan efforts.
Derry were content to haul everyone back into the rearguard, with Eoin Bradley isolated in attack. Operating as a sweeper, Danny Heavron provided security in front of the Derry full-back line, where Slaughtneil's 21-year-old full-back Brendan Rogers produced an outstanding county debut.
When Jim McCorry elected to make no changes at half-time it might have been seen as folly and after a shock red card in the second minute of the second half, it appeared Derry were well-placed to coast home.
Few in the ground managed to catch the incident, but eye-witnesses spoke of a coming together between Conaill McGovern and Enda Lynn. After consulting with his umpires at the dressing room end, referee Eddie Kinsella issued Burren man McGovern with a straight red.
Down immediately changed their shape and went for broke. The first couple of moves were not promising, such as Caolan Mooney's pass to O'Hare being cut out by the increasingly-influential McGoldrick on 41 minutes. The ball went straight up the pitch and Bradley fashioned a superb solo point, displaying his physical strength to move Derry into a four-point lead with 30 minutes left.
Conor Laverty's move to wing-forward changed the shape and when Rogers fouled Mark Poland, Paul Devlin was gifted a second free in two minutes from where he had missed the first. This time he iced it.
Peter Fitzpatrick was lucky to escape a round-the-neck challenge on Kevin Johnston with merely a yellow card to keep what they had on the pitch.
A McBride foul on Donal O'Hare led to Devlin's fourth free and he clipped another one two minutes later after a Heavron foul to leave a single point in it. Laverty's point from the Lone Moor Road sideline on 56 minutes had the Down team on level terms as some of Derry's key figures appear to tire on a rare afternoon of sun.
Johnston broke through the lines and went to fist over the bar, but just as it hung in the air and was about to drop favourably to Down goalkeeper Stephen Kane, substitute O'Boyle used his height to rise and fist over for Derry's first point in 21 minutes, nudging them ahead again with eight minutes remaining.
McCorry sprung Arthur McConville from the bench, the man who accrued four goals in the National League despite surviving off scraps of garbage for a lot of the time, and Niall Holly was detailed to follow him to the edge of the square.
Derry sub Terence O'Brien held onto the ball too long with three minutes left, prompting referee Kinsella to move the ball in closer for Devlin to apply another equaliser.
But just at that point, they lost their composure.
Devlin had a chance from play and kicked a wild wide, appearing to injure himself in the process. Jerome Johnston decided to have a dig from distance, but it completely lacked both conviction and accuracy.
From that kickout, Derry worked it patiently through the hands.
Bradley transferred it to the overlapping Johnston and he was subject to a desperate pull-down by retreating defender O'Hagan, who was given a black card before Bradley clipped over the 14-yard free.
Down had one last attempt, firing in a long high ball to McConville, but Holly got a strong fist to the ball, with the final whistle blowing straight after. Derry might have been worth it, but it was a skin of the teeth measure.
Derry now face the winners of next weekend's clash between Armagh and Donegal, on June 27.
Derry: T Mallon; D McBride, O Duffy, B Rogers; D Heavron, K Johnston, C McKaigue, C McFaul; N Holly, F Doherty; SL McGoldrick, M Lynch 0-5, 2f, E Lynn 0-1; B Heron, E Bradley 0-5, 3f
Subs: C O'Boyle 0-1, for Heron (53m), T O'Brien for Lynn (63m),
Yellow cards: McBride (23m), Holly and Heavron (56m)
DOWN: S Kane; D O'Hagan, L Howard, C McGovern; R Boyle, B McArdle, D Turley; C Mooney, P Fitzpatrick; P Devlin 0-6, 6f, K McKernan 0-2, C Maginn; M Poland, C Laverty 0-2, D O'Hare 0-1, 1f
Subs: P Downey for Maginn (48m), J Johnston for Fitzpatrick (59m), A McConville for Mooney (63m), N Madine for Devlin (69m),
Yellow cards: O'Hare (23m), Howard (32m), Fitzpatrick (48m), Mooney and Poland (56m)
Black cards: O'Hagan (71m, replaced by D O'Hanlon)
Red cards: McGovern (36m)
Referee: Eddie Kinsella (Laois)