COME FIVE O’CLOCK today, there will be 15 one-on-one battles in full flight in a small corner of London.

Each one of them could prove to have the winning and losing of the biggest prize in European club rugby.

But we’ve narrowed the field by five in an attempt to find the clashes that will be absolutely pivotal.

Cian Healy v John Afoa

Win this battle and anything becomes possible. The other side of the scrum is likely to prove no contest as Mike Ross squares up against the man with more demons than most on the hallowed of Twickenham, Tom Court.

Cian Healy is a mean scrummager, but he will be up against All Black John Afoa, the best operator on the park and (by extension) Ireland. For Ulster to win, they will need Afoa to suck penalties out of the Ireland loose-head. That will by no means be easy. Should Healy win parity in this area, then the blues could cruise.

Sean O’Brien v Chris Henry

The man Brian O’Driscoll described as Ulster’s key man is back in harness for Ulster. Though not a born seven, Henry has made himself into one over the past two years and he is as adept as any on this island at influencing the ruck.

Joe Schmidt has opted to leave his own groundhog, Shane Jennings, on the bench as he seeks to boost the set-piece options rather than the breakdown. It’s the same back row which started the final last year. We all know it ended well for Leinster, but only after Kevin McLaughlin was replaced by the former Leicester Tiger. Ulster will not give up a lead as easily as Northampton did.

Sean O’Brien has been struggling for some time now, and it is his prolonged stint on the wrong side of the scrum that is taking away from his wrecking-ball abilities in the loose. He’ll be pitted against Stephen Ferris in the loose, but on the ground he’ll need help to combat Henry.

Jonathan Sexton v Ruan Pienaar

These are the guy with the weight of a province on their shoulders and medals in their right boots. The colour of those medals will depend on their performance.

Not only will they need to be long and accurate off the tee, but they will also be tasked with kicking for position. Pienaar, despite being the scrum-half, must take the pressure of game-management off young Paddy Jackson and share the burden with Paddy Wallace.

Kicking will be much more important for Ulster, not only is it imperative that they limit the pace of the game with set-pieces, but the kicks must steer clear of Rob Kearney – who as a counter-attacker is unrecognisable from the player which starred for the Lions – and Isa Nacewa who are capable of tearing a loose defence to shreds.

Verdict: Leinster 17 – 15 Ulster

The last time: Memories of Ulster’s Heineken Cup triumph

Open thread: How do you thinkg the Heineken Cup final will fare?