This will tell us much about Leinster. They've backed themselves into quite a corner and both the circumstances of a brutally tough pool along with the scale of last week's performance and result demands an immediate and swift improvement. Most probably, it's win-or-bust time already too.
Sheer pride in the standards achieved by this organisation over the last decade or so ought to also have provoked a more focused and even angry response in Tuesday morning’s raft of meetings and in training thereafter. Certainly they can ill-afford 22 or so missed tackles and 24 turnovers, nor the lack of line speed in defence and lateral running with the ball.
And it still looks, on paper at any rate, like a strong team, most probably stronger than six days ago.
Leinster’s team selection in the light of those returning or those ruled out is something of a mixed bag, if overall seemingly on the positive side, especially with regard to their backline.
Most encouragingly, captain Isa Nacewa returns at fullback, while the return of Luke Fitzgerald and Ben Te'o should give them a stiffer and more potent midfield.
The ripple effect sees Fergus McFadden switched to his more customary slot on the wing, with Zane Kirchener and Ian Madigan dropping to the bench. Rob Kearney is still sidelined.
Quicken the tempo
More curiously, therefore, the 35-year-old Isaac Boss has returned to the starting line-up with Eoin Reddan, who turned 35 yesterday, dropped from the match-day 23 altogether (not much of a birthday present). This does not seem inclined to quicken the tempo of Leinster's game and so utilise the strengthened backline.
Up front, the trio of players who suffered concussion last Sunday are all ruled out, namely Richardt Strauss, Mike McCarthy and most damagingly of all, Seán O'Brien. Against that, Rhys Ruddock returns, while Kiwi lock Hayden Triggs makes his first European Cup start, while Cian Healy also returns to the frontrow along with Seán Cronin.
In the absence of O’Brien, the return of Healy, Cronin and Ruddock should improve their ball-carrying. McCarthy’s loss appeared to be acutely felt at scrum time and, mindful of this, Marty Moore’s recall to the bench is welcome.
Straight running
It would be a major surprise if Leinster don’t bring way more intensity, line speed and straight running to their performance than was the case last week, but once again the high, if largely enforced, amount of changes makes cohesion difficult after the major disruption of the World Cup.
Whereas Leinster have only a six-day turnaround, Bath haven’t played in a fortnight. Admittedly, Mike Ford’s team have not hit their straps like last season, when their European Champions Cup quarter-final loss to Leinster at the Aviva was followed by a free-scoring seven-game winning run that took them all the way to the Premiership final.
One ventures that they may have been a little too hasty for their own good in signalling the departure of Peter Stringer. The return of his quicksilver service to the starting scrumhalf position coincided with that seven-match winning run.
Furthermore, they have been missing their orchestrator in chief at outhalf in George Ford, who may or may not have been scarred by his World Cup jettisoning for the Welsh game courtesy of the English management's volte face.
Gnashing of teeth
They also missed Anthony Watson, who is given altogether more licence to counter or run from anywhere under the Bath regime. And of course, there was much gnashing of teeth, in Bath at any rate, over the swift post-World Cup exit of Sam Burgess. But it's still nothing like the after-effects apparently being felt in Leinster.
Ford is partnered by Chris Cook, with a settled midfield in the excellent Kyle Eastmond and Ollie Devoto, along with their customary mix of bludgeon and rapiers in the back three.
Their captain Francois Louw could do damage at the breakdown, and while their tight five may not be the most over-powering in the Premiership, it's worth noting that despite their seriously weakened frontrow in last season's quarter-final clash at the Aviva, for all their scrum superiority Leinster still struggled to put Bath away.
Indeed, with Ford twice cutting Leinster’s defence open for the game’s only tries, the home side were clinging on for dear life at the death. Bath also have the whiff of vengeance for that defeat, which hurt them acutely.
The Rec is a tight, cramped venue, yet not the most intimidating in the European map, and Leinster have never lost there. Indeed, they have won six of the sides’ seven previous meetings, and while Bath have only won two of their 13 matches against Irish opposition in the European Cup, last week’s defeat was only Leinster’s third in their last 17 matches against English opponents.
It’s said that the best way of overcoming a fall is to hop straight back on a bike. That Leinster have such a quick opportunity for redemption could be a blessing.
Big games from the big guns, Healy, Ruddock, Jamie Heaslip, Sexton, and indeed Fitzgerald, Te'o and Nacewa, along with an early try, could both liberate Leinster and infuse them with confidence.
More advanced
Even so, Bath are at home, with every incentive, are more settled, seemingly less hungover and way more advanced in their way of playing under Ford than Leinster are under their new coaching ticket.
Leinster are also coming from such a low ebb last week. If they do somehow turn last week’s defeat into a win here, it really would be some turnaround.
Bath v Leinster, Recreation Ground, Saturday, 3.15pm (BT Sport Europe)
BATH: A Watson; S Rokoduguni, O Devoto, K Eastmond, M Banahan; G Ford, C Cook; N Auterac, R Webber, H Thomas, D Day, D Attwood, M Garvey, F Louw (capt), L Houston. Replacements: R Batty, N Catt, M Lahiff, S Hooper, A Faosiliva, N Matawalu, R Priestland, T Homer.
LEINSTER: I Nacewa (capt); F McFadden, B Te'o, L Fitzgerald, D Kearney; J Sexton, I Boss; C Healy, S Cronin, M Ross, D Toner, H Triggs, R Ruddock, J Murphy, J Heaslip. Replacements: J Tracy, J McGrath, M Moore, D Ryan, J van der Flier, L McGrath, I Madigan, Z Kirchner.
Referee: Jerome Garces (France)
Previous meetings: 2014-2015 quarter-final: Leinster 18 Bath 15. 2011-12: Leinster 52 Bath 27; Bath 13 Leinster 18. 2005-2006: Bath 23 Leinster 35, Leinster 19 Bath 22. 2004-05: Bath 23 Leinster 27, Leinster 30 Bath 11.
Betting: (Paddy Power): 2/5 Bath, 17/1 Draw, 21/20 Leinster. Handicap odds (Leinster +6pts) 10/11 Bath, 25/1 draw, 10/11 Leinster.
Forecast: Bath to win.
