Challenge Cup/Round One, Second leg: The mathematics of the situation appears simple. Connacht must win by 15 points to progress to the second round and overhaul the first-leg deficit.

There are other avenues of progress in the competition open to the Irish province as there are a couple of spots to be won by the two teams that end up on the losing side but with the narrowest margins of defeat over the two legs.

Michael Bradley would prefer not to have to buy a ticket for the lottery, instead demanding of his team they atone for what was a performance pockmarked by second-half errors. Trailing just 3-0 at the interval last week, Connacht didn't remain that resilient in the second half. Full back Mark McHugh rescued them late on from what would otherwise have been a virtually impossible assignment.

These two teams have been intertwined over the last few seasons and it's been difficult to slip a wafer thin mint between them after excellent two-legged battles.

In some respects the fact Connacht have to claw back a significant points differential will make it easier to attune minds.

Occasionally having played well away teams believe all they have to do is turn up at home and everything will pan out. Connacht don't have that luxury but they do have the wherewithal to significantly improve.

The half-back pairing has been changed with Paul Warwick and Chris Keane coming in while Conor McPhillips is back on the wing.

Narbonne have made six changes to the side that won last week including replacing their front row. They will be keen to disprove the old adage that French teams don't travel well. Three weeks ago they travelled to Castres in the French Championship and won.

Connacht will need to be patient and remove the errors that littered last week's display. The decision to provide free admission to those wearing Connacht jerseys should give the Sportsground a little colour this afternoon.

CONNACHT: M McHugh; M Mostyn, D Yapp, J Downey, C McPhillips; P Warwick, C Keane; R Hogan, B Jackman, S Knoop, A Farley, C Short, M Swift, M Lacey, J Muldoon. Replacements: John Fogarty, D McFarland, M Carroll, P Neville, C O'Loughlin, E Elwood, T Robinson.

NARBONNE: L Ferrers; F Lartigue, D Douy, JP Viard, J Candelon; N Nadau, J Seron; R Palomera, F Rofes, L Martine, M Sierra, P Short, D Hunter, J M Bisaro, B Bedes. Replacements: M Bigou, L Zanini, M Dehaese, S Barthes, L Baluc Rittener, M Siro, P O Julien.

Referee: Sean Davey (England).

Verdict: Connacht to win.