CAN lightning really strike twice?

Or was Celtic's victory over Barcelona last year really a flash in the pan?

All will be revealed in just over 24 hours when the clubs meet at Parkhead in the Champions League again.

Without the presence of the world's best player, Lionel Messi, the occasion has lost a little of its sparkle while Celtic's chances have undoubtedly received a massive boost.

But to believe Barca are a one-man team is to invite major trouble to your door.

And the likes of Xavi, Andres Iniesta, Pedro Rodriquez, Adriano and £50million new boy, Neymar - who will be sampling the special Celtic Park atmosphere for the first time - will be intent in delivering it.

It could be argued what was a tough job for Neil Lennon in preparing his players for this massive challenge has actually been made that bit harder by the withdrawal of Messi as all the work he has done up until now has been based upon stopping a team with the Argentinian at its heart.

Now new boss Gerardo Martino has to come up with plan B, and perhaps even he isn't quite sure what that will be.

Will they be slightly less attack-minded? Will Neymar - a sub in Saturday's 2-0 win over Almeria - become the key figure? Will they attempt to reduce the number of passes to get forward and adopt a more direct approach?

Only when the whistle goes tomorrow night will Lennon and everyone else find out.

For now, the Hoops boss can only focus on his own players and tactics, building in a flexibility to cope with the Messi-less Barca they are about to encounter.

The 5-2 win over Kilmarnock has at least left Lennon sure his own men are good to go, in particular Georgios Samaras, that hero of so many European nights, who warmed up with the first-ever hat-trick scored in the SPFL Premiership.

With Kris Commons and sub Amido Balde also getting on the score sheet, the only concern to come out of Rugby Park was the concession of two goals in a six-minute spell, Sammy Clingan and Sean Clohessy bringing the score back to 3-2 before half-time.

Such lapses will be severely punished by Barcelona, and Lennon accepts every one of his players must lift their game another notch or two, with the exception of Sami, who showed at the weekend he is already there.

The emphasis will be on playing as a unit, and Lennon has already reminded his Bhoys how potent a force they can be when they stand together.

"It is going to be what we do as a team that matters, and that's why we want them to look again at the DVD of last year's game with Barcelona," said Lennon.

"I want them to see how well they worked, and things like the distances there was between one another when Barcelona had the ball.

"Again, we need to limit the number of chances Barcelona are permitted, and to maximise the chances we get when they come."

They did this to great effect against Killie, the big guns back after the misfiring midweek performance against Morton in the League Cup.

Losing to a lower division club cut Lennon to the core. Watching it happen at home stuck the knife even deeper.

It will be a completely different atmosphere tomorrow with the stadium at bursting point, and the Champions League theme tune booming out to remind everyone this is yet another very special occasion.

Until Juventus came to Glasgow and won the first leg of their Last 16 tie 3-0, Barca held the honour of being the only side to win at Parkhead in the Champions League proper.

They have actually done that twice, winning 3-1 in the group stage in 2004, then 3-2 in the last 16 four years later.

The Celtic boss knows the psychological importance of defending the 'Fortress Parkhead' reputation, and how damaging it could be to have another chip in that wall.

However, his ambitions lie not only within the confines of home.

Lennon explained: "There is no question the home form is pivotal, but I want to add away form to that as well, and to pick up points on the road because we can't always guarantee wins at home.

"The law of averages is that we are going to get beaten at home at some point."

Should that defeat come tomorrow night, it would leave Celtic with no points from their opening two games, and trailing Barca - and perhaps AC Milan - by six.

It's an unpalatable prospect, but one which does not induce any sense of panic in Lennon.

He would not be happy, but neither would he be throwing in the towel in the pursuit of another Last 16 place.

"I have already said this because there would still be four games to go in the group," said the manager.

"It would just make the Ajax double-header, which follows, pivotal.

"But, again, you don't know what the score will be in their game against Milan in Amsterdam tomorrow.

"Regardless, if Milan get a point or get a win, there will be a bit of catch up to do. But I think we can turn Milan over at Parkhead. I think we are capable of doing that."