Simply put, if Northampton avoid defeat in Ravenhill Road tonight they will win Pool Six.

Even if they lose to Ulster the 2000 champions will automatically qualify for the quarter-finals unless one of the following occurs: (a) Ulster score four more tries than them; (b) Ulster score three more tries and win by a 24-point margin; (c) Northampton lose by 12 points and fail to score a try.

If (a) and (b) occur then Ulster would overtake Northampton at the head of the group and if (c) happens Biarritz would do so assuming they account for Cardiff tomorrow afternoon.

But Ulster's proud feat of never losing a European game at home is a record that could come under some serious pressure. Having lost the away fixture to Northampton 32-9, (who won the match scoring two tries to nil) Ulster have a large turnaround to perform for what is a long shot at securing the pool.

According to Northampton coach Wayne Smith his side will forget about the complexity of the permutations and simply go for the win in Belfast.

"We have to win for us to go forward. We haven't spoken about the possibilities," said Smith. "It's amazing what a win like last week's against a good team can do for us but we have to follow that up."

Former Wallaby Peter Jorgensen has been selected in the starting line-up after scoring the match-winning try against Biarritz last Saturday. The centre had to settle for a place behind 20-year-old Chris Hyndman but has fought his way back into favour.

The English side will be without flankers Andrew Blowers and Scottish captain Budge Pountney, so their pack remains unchanged from last weekend although obviously weakened by the omission of two strong players. In the backs 22-year-old James Brooks will also start on the wing in place of Spaniard Oriol Ripol, who he replaced last weekend.

Ulster coach Alan Solomons has stressed that Ulster should concentrate on winning the match first and to that end has announced an unchanged Ulster side for the first time in 14 matches, the squad having been severely hit by injuries since the beginning of the season.

Solomons has particularly shown faith in prop Simon Best, who proved himself last week against Cardiff in the absence of the suspended Justin Fitzpatrick, who is on the bench at the expense of Clem Boyd.

So too will two-try Neil McMillan look for another inspired performance in a strong back row along side Tony McWhirter and captain Andy Ward. The 21-year-old in his first season as a contracted player said earlier in the week that home advantage would account for 10 to 15 points.

That has traditionally shown to be the case and with winger Ben Cohen and scrumhalf Mat Dawson just coming back from injury, the hope is that neither of those two key English players will be on the top of their form.

Dawson was irked when it was put to him that going to Ravenhill was bad enough but capped by having to play the climactic match against former champions.

"Why should we be afraid? We're also former champions so I don't see what that has to do with it. We can win there and put the debate to sleep," said Dawson.

But the battle will be up front and Ulster will have to deny the visitor's dangerous back line to get moving. This is one of Ulster's toughest asks for some time.

ULSTER: B Cunningham; J Topping, R Constable, S Stewart, S Coulter; D Humphreys, N Doak; R Kempson; M Sexton, S Best, G Longwell, J Davidson, A Ward (Capt), N McMillan, T McWhirter. Replacements: J Fitzpatrick, P Shields, M Blair, R Nelson, K Campbell, J Cunningham, S Young.

NORTHAMPTON: N Beal; J Brooks, P Jorgensen, J Leslie (Capt.), B Cohen; P Grayson, M Dawson; T Smith, S Thompson, M Stewart, S Williams, R Hunter, G Seely, M Soden, M Connors. Replacements: D Richmond, C Budgen, R Morris, J Phillips, I Vass, M Tucker, J Sleightholme.

Referee: J Dume (France).

Previous meetings: (EC 2002-03): Northampton 32, Ulster 9.

European Cup formguide: (Northampton) Northampton 32 Ulster 9; Biarritz 23, Northampton 20; Northampton 25, Cardiff 11; Cardiff 0, Northampton 31; Northampton 17, Biarritz 14. (Ulster) Northampton 32, Ulster 9; Cardiff 21, Ulster 33; Biarritz 25, Ulster 20; Ulster 13, Biarritz 9; Ulster 25, Cardiff 6.

Verdict: Northampton.