The Exiles dominated an error-strewn contest at Ruislip and led by eight points at the interval. But they managed only a solitary point in the second half and were punished for their profligacy when Paul Broderick levelled matters with the final kick of the game.
“Unfortunately today, there were too many wrong decisions made by players when the chances were there, and that was the big killer,” said Coggins.
Barry Mitchell’s 18th-minute goal had put London in control, and an own-goal from Barry-John Molloy gave the hosts a 2-6 to 0-4 advantage at the break.
London wasted numerous chances to put the game to bed and were punished as Carlow hit the final five points of the game.
“There is a lot of character in this team and I think we’ve proved that today,” said Carlow boss Anthony Rainbow.
“We came back from seven points down against Antrim, and we came back from eight down here. The players just need to believe in themselves a small bit more.”
Scorers for London: B Mitchell (1-0), BJ Molloy 1-0 (own-goal), M Gottsche (0-2), A Bradley, L Mulvey (f), A Moyles (f), J Feeney, D Ryan (0-1 each).
Scorers for Carlow: P Broderick (0-5, 2fs), G Dempsey (0-2), S Kinsella (f), J Kane, D Foley (f), W Minchin, D St Ledger, J Kennedy (f) (0-1 each).
LONDON: D Traynor; P Butler, S Curran, B Collins; D McCarthy, S Mulligan, D Ryan; M Gottsche, M Carroll; J Feeney, B Mitchell, A Bradley; A Moyles, L Mulvey, M Miskelly.
Subs: S Hickey for Miskelly (24), C McCarron for Mitchell (45), L Colfer for Moyles (48), S Hannon for McCarthy (50), D Dunleavy for Feeney (52), M Walsh for Collins (65).
CARLOW: P Coady; BJ Molloy, S Mernagh, R Mahon; H Gahan, D Bambrick, B Kavanagh; M Ware, D Foley; C Coughlan, M Meaney, J Kane; P Broderick, G Dempsey, S Kinsella.
Subs: W Minchin for Ware (24), D St Ledger for Kinsella (55), C Moran for Foley (64, BC), J Kennedy for Dempsey (65).
Referee: B Rice (Down).