A  defining moment in Connacht's season takes place in the unusual surrounds of Corinthian Park when they seek to retrieve a 15-point deficit from the first leg of their Parker Pen Challenge Cup second round tie in tomorrow's second leg against Narbonne. The situation is clear: it's win or bust.

Effectively Connacht must win by at least 16 points or their season will be to all intents over before Christmas - which wouldn't be a source of Yuletide merriment, all the more so given some of the IRFU powerbrokers would then have more reason to sharpen their knives.

The prize at stake then goes way beyond a third round or quarter-final meeting with either Leeds Tykes or, more probably, Pontypridd, who lead Leeds after the first leg by 14 points and unceremoniously ended Connacht's five-game winning start to the Celtic League with a stunning 40-point drubbing of Steph Nel's men last September.

"It's do-able," says Connacht's chief executive Gerry Kelly, echoing the words of Nel after the first leg.

"It's a big ask but you never know what could happen if we get amongst them and score early on."

Based on last season's championship results, Narbonne would be France's third-strongest entry in the Parker Pen Cup.

They've made five changes from the first leg, at right wing, outhalf and three in the tight five, with Argentinian hooker Mario Ledesma an injured bystander, though it shouldn't weaken them unduly.

The old adage about the need to obtain an early score or two and sow the seeds of doubt in French minds has rarely seemed more appropriate.

Granted Connacht tend not to win matches by big scores but at least they know what's required of them, and with a big crowd likely to rally round them in their hour of need, that could be vital entering the final quarter if the target is remotely achievable.

CONNACHT: M McHugh; T Robinson, D Yapp, S Moore (capt), W Munn; E Elwood, E Reddan; R McCormack, M Uijs, P Bracken; D Browne, R Frost; C Rigney, M Swift, J O'Sullivan. Replacements: D McFarland, J Flannery, E Peters, J O'Connor, C Keane, G Duffy, D O'Sullivan.

NARBONNE: P Bazini; S Hunt, D Douy, J Gillingham, G Tutard; C Rosalen, L Balue; A Martinez, S Petit, L Martine, D Hunter, O Olibeau, G Belzons, A Hill, L Bauc Rittener, X Guillemet, B Stortoni, J Gendre, M Siro, M Sierra, O Seux, S Guy

Referee: R Goodliffe (England).