London Irish's hopes of making the Heineken Cup quarter-finals were dealt a mortal blow on Sunday as they fell 31-22 to the Scarlets in Llanelli.
Trailing 22-10 with 20 to go and with fly-half Rhys Priestland misfiring off the tee, blindside Rob McCusker capitalised with two tries on a performance of huge spirit, spearheaded by the effervescent David Lyons, with Priestland finding his radar once again in the nick of time to convert both and give the Scarlets the lead.
Then Jonathan Davies stormed home for his second try in the final minute to deny the Exiles even a bonus point. Irish now head into next week's clash against Leinster at home, needing a bonus point win and denying Leinster anything to even stand a mathematical chance of qualification, but the body language at the final whistle suggested they will spend much of the week simply recovering from this defeat.
Moreover, the bonus point win for the Scarlets means they also now stand a mathematical chance of qualification, something not lost on the crowd who raised the roof at the end.
Focus will shift to the Eiles though, whose season is beginning to run out of steam. There were mutterings between the coaches at some of the penalties awarded to the Scarlets by the referee, but the Exiles set their stall out to compete at every breakdown. If you live on the edge of the law, occasionally you will totter over. Monsieur Garces' officiating was some of the best seen at this level this season.
As was the rugby. Both sides ran the ball with aplomb, the Irish because they needed four tries, the Scarlets because they had nothing to lose and because it is still evidently an integral part of their culture.
The game began at a rapid rate of knots, with three tries in the first 15 minutes - two for Irish.
Homer collected the first, rounding off impressive work by centre Seilala Mapusua and England full-back Delon Armitage, but the Scarlets staged an immediate response.
Like Irish, they looked to spin possession wide, and their adventure was rewarded when wing Andrew Fenby sprinted outside his opposite number before sending the supporting Davies sprinting over.
Priestland added the conversion for a 7-5 advantage, yet Irish quickly regrouped to carve out an opening for Paice.
Lamb's conversion opened up a threatening lead, and it looked as though Irish would take charge when Scarlets lock Lou Reed was sin-binned for deliberate obstruction on Irish scrum-half Paul Hodgson.
Lamb slotted the resulting penalty, but Irish were unable to capitalise on their temporary one-man advantage and Priestland ended the half by kicking a long-range penalty following his earlier misses.
Priestland, though, turned villain 12 minutes into the second period, failing to gather Irish wing Peter Hewat's steepling kick, and with the Scarlets defence ball-watching, Hala'ufia collected a kind bounce and cruised clear.
It was a soft score for the Scarlets to concede, although they kept plugging away despite facing a 12-point deficit entering the final quarter.
And their resilience was rewarded 15 minutes from time when McCusker showed a considerable turn of speed for the Llanelli side's second try, converted by Priestland.
Irish, who had been chasing a bonus point, suddenly found themselves scrapping just to stay in front, with Booth looking for stronger half-back control by sending on Peter Richards and Chris Malone as the clock ticked down.
North Walian McCusker though, had other ideas, claiming his second try - it required confirmation from television match official Daniel Gillet - and Irish could only stare in disbelief as Priestland rifled over the touchline conversion.
The visitors mounted an inevitable onslaught during a frenzied finale, yet the Scarlets were not to be denied after putting themselves in pole position.
Irish repeatedly ran possession at them, but a defensive structure moulded by former Australia international defence coach John Muggleton held its shape amid intense pressure.
Garces' final whistle - immediately after Davies finished Irish off - sparked scenes of wild celebration, with the Scarlets travelling to Brive next weekend knowing that another victory could see them finish second in the group.
For the Scarlets:
Tries: Davies 2, McCusker 2
Cons: Priestland 4
For London Irish:
Tries: Homer, Paice, Hala'Ufia
Cons: Lamb 2
Scarlets15 Daniel Evans, 14 Morgan Stoddart, 13 Sean Lamont, 12 Jon Davies, 11 Andrew Fenby, 10 Rhys Priestland, 9 Martin Roberts, 8 David Lyons, 7 Josh Turnbull, 6 Rob McCusker, 5 Dominic Day, 4 Lou Reed, 3 Deacon Manu, 2 Ken Owens, 1 Iestyn Thomas.
Replacements:16 Emyr Phillips, 17 Phil John, 18 Jamie Corsi, 19 Damian Welch, 20 Jon Edwards, 21 Lee Williams, 22 Daniel Newton, 23 Gareth Maule.
London Irish:15 Delon Armitage, 14 Peter Hewat, 13 Elvis Seveali'i, 12 Seilala Mapusua, 11 Tom Homer, 10 Ryan Lamb, 9 Paul Hodgson, 8 Chris Hala'Ufia, 7 Steffon Armitage, 6 Richard Thorpe, 5 Bob Casey, 4 Nick Kennedy, 3 Faan Rautenbach, 2 David Paice, 1 Clarke Dermody.
Replacements: 16 Danie Coetzee, 17 Dan Murphy, 18 Paulica Ion, 19 Kieran Roche, 20 Gary Johnson, 21 John Rudd, 22 Peter Richards, 23 Chris Malone.
Referee: Jerome Garces