UEFA Cup Quarter-final, second leg:Liverpool v CelticTom Humphries, reporting from Liverpool, says Martin O'Neill's tactical nous could win out

So spring has barely sprung and Liverpool and Celtic meet in a match which could define their seasons. In the absence of league titles, annexing the secondary European competition will not be sufficient compensation for the more rabid supporters of either side, but it will take the bare look off the cupboard.

Given the nature of events elsewhere in the world, the christening of this game as the "Battle of Britain" seems a little odd and distasteful now. Besides, Liverpool's cerebral, some would say dull, approach has brought them to the cusp of success.

They travelled to Glasgow last week looking to limit the damage and perhaps score an away goal. Having had their crossbar rattled and their net breached in the opening minutes, snatching a goal through the unlikely offices of Emile Heskey at Parkhead was sufficient to douse that game.

Speaking of dousing: El Hadji Diouf will be a loss to Liverpool at Anfield tonight. As has been pointed out ad nauseum this week, the home side need to do more than sit back and absorb pressure for 90 minutes. The Senegalese spit-shame-star, as the more alliterative tabloids have identified him, not only brings a little unpredictability to Liverpool's rather conventional attack but he works hard covering back and breaking the rhythm of opposition build-ups.

For Liverpool that will be the key. When Celtic enjoy parity at midfield and start stretching teams through their wing backs they are tough to beat. Liverpool will be conscious that Michael Owen while always, in theory, a threat at Parkhead, was shepherded well by Bobo Balde and Johan Mjallby. As for Heskey, his next goal is scarcely due before Christmas.

If Liverpool are to succeed they need to add a spark of inventiveness to their familiar plan. We know they can defend. Sami Hyypia, whose influence is all over the Liverpool side, coped comfortably well with the diet of high balls which Celtic pumped towards Henrik Larsson after Celtic's early goal.

Liverpool are big and muscular in defence and Celtic have experienced a drop in the quality of their crosses since the departure of Lubo Moravcik. The danger for Liverpool lies in Celtic's flair for set-pieces and in the sort of penetration they are capable of when their dander is up.

Celtic blew hot and cold last week, looking their best when they surged forward early on. Larsson's goal heated their blood, and by sheer dint of numbers pushing forward, mutating their 3-5-2 into a 3-4-1-2 formation, they smothered Liverpool for a while. But when they got suckered by the equaliser they allowed the game to go quiet and permitted Liverpool sufficient possession to achieve a level of comfort they would have thought unlikely before the visit to Parkhead.

Something a little more thoughtful about the Celtic approach tonight would be useful. Liverpool, when they were allowed to string passes together, looked a better team than they actually are last week. Martin O'Neill will want to see his side's workrate distributed more evenly throughout the 90 minutes. Less frenzy in search of the breakthrough. Less permissiveness in terms of what Liverpool can do with the ball.

O'Neill is a devout believer in his formation and will lay his stall out in predictable fashion. Within the five-man midfield, however, the allocation of tasks may be different. Danny Murphy can be prosaic enough, but left largely unattended last week he was given access to the heart of the game. With Neil Lennon stretched and underperforming, Celtic struggled for long periods with Murphy and Dietmar Hamman. Chris Sutton, whose task it is to shuttle between the front pair and the midfield, seemed to lack the pace to cover adequately and his absence tonight may prove to be a thinly-disguised blessing.

O'Neill will look perhaps to use a player less interested in commuting and more able for tackling. In that regard, Alan Thompson, by instinct a central midfielder rather than a wing back, represents an option who could take the pressure off Lennon and Stilian Petrov. Thompson was injured early last week and replaced by Steve Guppy. Paul Lambert, who made way for Sutton last week, has claims.

Offensively, Celtic's main option will still be the cross. Young Jamie Smith did well in that regard for them on the right wing last week, but it would perhaps be too much to hope that he would get so much change out of John Arne Riise two weeks running.

Celtic will miss the experience and pace of Didier Agathe, but don't lack for options out wide. Smith can play either wing, and Thompson or Guppy are both capable of doing damage out wide, although O'Neill seems to have decided that Petrov's future is as a central midfielder.

Throughout this competition Celtic have travelled well, from Blackburn to Vigo to Stuttgart. And O'Neill's record of plotting for these big occasions is good, especially against Liverpool whom he beat three times in three years at Anfield when managing Leicester.

The smart money says that Liverpool should be composed enough to prevail, but that has been said about Liverpool many times this season. Passion and desire to count then. O'Neill's stock to rise still further.

UEFA Cup Quarter-final, second leg: Liverpool v Celtic

(Network 2, BBC 1, 8.05)