How to chuck away a 21-point lead in one easy lesson. That Leinster's season, which promised so much at one point, should end in such an anti-climax was appropriate for this was their season in microcosm.
Their opening European Cup victory over Llanelli was their fifth win in a row, at which stage they were also leading the interprovincial championship after four rounds. Last night's win that got away was their sixth defeat in seven games.
The mood seemed to permeate Donnybrook even before kick-off. The 4,000 crowd was discernibly more anxious. "The wheels have come off, and they came off badly, and it hurts," conceded Leinster coach Mike Ruddock.
Leinster have generally started well, sometimes threatening to run away with games when their own patterns of play are dominant. But once games have started to turn against them, it's as if the team is devoid of savvy and leadership. They nearly tossed away a 19-0 against Connacht. They have since squandered leads of 17-8, against Stade Francais, 17-0, against Connacht, and 10-0, against Begles/Bordeaux. Most spectacularly, they squandered a 21-0 lead, established in the first quarter, last night.
For the first quarter, there was an urgency to Leinster's play and they ran everything. Then their line-out gradually disintegrated, they adopted more of a kicking game, first-up tackles were missed as three soft tries were conceded before the break and there seemed no organisation off tapped Llanelli penalties. Even their initially strong scrum began creaking. When they fell behind Leinster began playing catch-up which resulted in anxiety-filled handling errors.
In mitigation, there's been an horrendous injury list. They missed Victor Costello, the demoted Pat Holden (for his tackle count and work-rate in the tight five) and Trevor Brennan last night - although the latter's replacement, Declan O'Brien, had a good game and scored two tries.
The first came when he was driven over, like a knife through butter, off his own line-out take 10 metres out.
From Scally's quick tap penalty, Emmet Byrne supported well, McGowan stepping inside his man off recycled ball to score under the posts - though there was a distinct doubt as to whether he grounded the ball. Then from a Colin McEntee pick-up off the base of the scrum, Kevin Nowlan burst through over the gain line, and a pick-and-go drive by the pack culminated in O'Brien plunging over again. McGowan converted all three. Happy days. Not.
Thereafter, Llanelli began moving the ball beyond Leinster's four-up defence and using the pace of their outside three to skin the home side out wide. And outscore the home side by six tries to nil. Llanelli were definitely the more expansive side and probably deserved to win.
The first try was a case in point, Wayne Proctor coming across his wing to break out from deep, and then appearing on the end of good handling all across the line to score by the flag.
The second try was particularly soft. Ian Boobyer scored the first of a rare, brotherly hat-trick when wriggling out of Gabriel Fulcher's tackle and bouncing off McGowan to score from 40 metres out.
Jones converted and deep into first-half injury-time, Neil Boobyer skirted up the touchline from another quick tap penalty to elude Emmet Byrne and score wide out, making it 21-17.
Leinster regrouped and should have been awarded a try when Pat Ward clearly touched down off a Hubie Kos take and line-out drive. However, as was the case on two other occasions, the unimpressive Joel Dume was badly positioned.
In any event, McGowan kicked a short-range penalty, but successive missed throws by Shane Byrne and a sliced touch kick by McGowan allowed Llanelli to pin Leinster back. Chris Wyatt crossed for a try after the Llanelli pack had taken on a Mike Voyle catch. Jones's touchline conversion drew the sides level.
Proctor again came across field to out-sprint the cover and stretch out to score after Ciaran Scally had stopped him short.
Cue panic stations and catch-up rugby. A midfield turnover, when Shane Horgan's pass was intercepted, saw Neil Boobyer kick ahead and Roddy Boobyer won the race for the touchdown.
A draw might have sufficed to earn Leinster a quarter-final place, but though they drove over from a line-out and briefly had the Llanelli scrum in trouble, their last chance went when Girvan Dempsey was forced into the corner flag.
At least Llanelli put them out of their misery. There's no need to wait for the Begles/BordeauxStade Francais result now.
Good night Donnybrook. Last out turn out the lights.