London held off a late Sligo fightback to knock the Yeats County out of the Connacht Championship and secure a first win in the province in 36 years.
Lorcan Mulvey's goal put London on the way to a famous win in the first half as a slack and wasteful Sligo side trailed by four at the break.
Padraig McGoldrick, a Sligo-man that missed a penalty in the first half for the home side, was sent off to give Kevin Walsh's side hope early in the second period.
Sligo battled back to within a point but when they struck the crossbar in the final minute of added-time, it meant London secured a shock 1-12 to 0-14 win to set up a semi-final meeting with Leitrim.
It is London's first provincial triumph since a 1977 win over Leitrim, the same county they will face in a Connacht semi-final on Sunday, June 23.
The visitors actually opened the scoring with just 30 seconds on the clock when a shot from Adrian Marren was pushed over the crossbar by London goalkeeper Declan Traynor.
However, it was the 20th minute before Sligo scored again.
Mark Gottsche levelled the sides with a free from 50 yards out, before London found the net in the 13th minute to move into a lead that they would never relinquish.
After some good work by Greg Crowley, Ciaran McCallion surged through the Sligo defence before offloading to former Cavan player Lorcan Mulvey, who finished neatly beyond Philip Greene in the Sligo goal.
That score put the momentum firmly behind London and they capitalised with three unanswered points from Mulvey, Gottsche and the excellent Cathal McGee.
Marren finally broke Sligo's barren spell and Mark Breheny added another point from a free with 23 minutes on the clock, after which Gottsche put London back into a five-point lead with a '45'.
London had former Sligo player Padraig McGoldrick at corner forward, but he had an afternoon to forget. After Greg Crowley was brought down by Philip Greene, the Sligo goalkeeper made amends by saving McGoldrick's penalty.
Breheny and ex-London defender Charlie Harrison added to Sligo's tally either side of a Cathal McGee point to leave the visitors trailing by 1-06 to 0-05 at the interval.
In perfect conditions for Championship football at Rusilip, the breeze behind Sligo in the second half was not strong enough to be a decisive factor and they fell further behind through an early McGoldrick free.
Breheny hit back for Sligo but London again began to pull away, kicking three without reply – from McGee, Gottsche and Barry Mitchell – to lead by 1-10 to 0-06.
But Sligo were thrown a lifeline 15 minutes into the second period when McGoldrick was given his marching orders after being shown a second yellow card for a foul on Neil Ewing.
McGoldrick's dismissal eventually sprung Sligo to life and they hit eight points in the final 17 minutes – two from Harrison, three from Tony Taylor, one each from Breheny and Pat Hughes, as well as an outstanding effort from substitute Niall Murphy.
But London, thanks to points from Mulvey and Sean Kelly, remained a point to the good in the dying moments as Sligo's onslaught continued.
With one last throw of the dice, Hughes received a pass from Brian Curran but he punched the ball against the crossbar with the last play of the game and London turned their attentions to a rare Connacht semi-final appearance next month.
LONDON: Declan Traynor; Kevin Lynam, Stephen Curran, Dave McGreevy; Seamus Hannon, Shane Mulligan, Tony Gaughan; Mark Gottche (0-04, 0-01f, 0-01 '45'), Caolan Doyle; Greg Crowley, Ciaran McCallion, Barry Mitchell (0-01); Padraig McGoldrick (0-01, 0-01f), Lorcan Mulvey (1-02), Cathal McGee (0-03).
Subs used: Brian Collins for Lynam (17 mins), Paul Geraghty for Mitchell (51), Sean Kelly (0-01) for McCallion (60), Damien Dunleavy for Doyle (67), Eamon McConville for Mulligan (68).
SLIGO: Philip Greene; Keelan Cawley, Ross Donovan, Neil Ewing; Charlie Harrison (0-03), Adrian McIntyre, Brian Curran; Stephen Gilmartin, Tony Taylor (0-03); Brendan Egan, Pat Hughes (0-01), Shane McManus; Mark Breheny (0-04, 0-02f), Adrian Marren (0-02), Frankie Quinn.
Subs used: James Kilcullen for Gilmartin (47 mins), Niall Murphy (0-01) for Egan (51).
Referee: Padraig O'Sullivan (Kerry)