A SPECTACULAR display of finishing by corner-forward Gerard Hennelly underpinned London's victory at the Athletic Grounds.
Hennelly, thriving on a steady supply of quality possession, had pocketed five points by the break, at which stage his side led by 0-12 to 0-7.
London sustained their onslaught in the second half.
The visitors streaked clear at 0-18 to 0-11 and looked set to turn the screw.
But referee Gerard Duffy turned down a strong Armagh claim for a penalty when Conor Corvan was upended in the 56th minute and then disallowed a goal from the same player because of an earlier foul.
Armagh's Cathal Carvill and then London centre-forward James Regan were red-carded following off-the-ball incidents.
Man of the Match: G Hennelly (London)
SCORERS – London: G Hennelly 0-11 (3 '65s', 5f), M Duggan 0-5, K Bolger 0-3, C McAlinden, S Lambert 0-1 each. Armagh: D Coulter 0-7 (7f), M Lennon 0-2, K McKernan, R McGrattan, D Carvill, C Carvill, C Corvan 0-1 each.
LONDON – D Russell 6; P Lane 6, D Healy 7, B Moroney 6; D Maher 6, J Walsh 8, S Frawley 6; H Vaughan 6, C McAlinden 6; S Lambert 6, J Egan 6, M Duggan 7; G Hennelly 9, L Hands 6, J Maher 6. Subs: B Regan 6 for Moroney (h-t), S Keane 6 for Frawley (47), T Dunne 7 for Hands (53), K Bolger 8 for Lambert (63).
ARMAGH – S Doherty 6; C Devlin 7,C Clifford 7, B Breen 6; J King 6, R McGrattan 7, P Hughes 6; J Corvan 6, K McKernan 6 ; M Lennon 7, R Gaffney 6, D Carvill 6; C Carvill 6, C Corvan 7, D Coulter 8. Subs: S Gaffney 5 for Hughes (37), F Bradley 6 for McKernan (58), M Maguire 5 for Carvill (65), C McKee 5 for J Corvan (68).
REF – G Duffy (Antrim)