ONE speculates feverishly as to the precise content of Neil Lennon's address to the troops on Sunday.

The words may be forever lost in the mists of Lennoxtown, but the message stayed with his players.

Celtic came out at Parkhead last night with such a belligerence that one believed they were not playing in a quarter-final of the Scottish Communities League Cup but rather storming a trench full of St Johnstone players who had insulted their mothers and dishonoured their sisters.

The half-time score of 3-0 did not fully testify to the overall domination enjoyed by Celtic. The final result of 5-0 sees Celtic into the semi-finals, but Lennon's satisfaction will owe much to his relief and delight at watching his side return to the energetic form that preceded the 2-0 loss to Kilmarnock on Saturday.

This was a performance that sparkled with pace and drive and was underpinned by a solid certainty of purpose. Playing in a straightforward 4-4-2, the returning heroes of Scott Brown, deployed in a wide position, Victor Wanyama playing in central midfield and Gary Hooper leading from the front, steered their team to a comprehensive victory.

The Celtic manager had blamed himself for the omission of those three influential players to the detriment of the team on Saturday. They returned with a vengeance last night but were surpassed by the marvellous play of Kris Commons, a clever and assured player who made two goals, scored two goals and presumably made the half-time tea.

However, if the Scotland internationalist was in irresistible form, the three posted missing for rest and recreation on Saturday also made their presence felt.

Brown has a quality that is almost infectious in that his limitless energy seems to add vim to the side. He was taken off after 63 minutes and if this was not his finest hour then it certainly was productive in the response he drew from his team-mates. Hooper, who was replaced at half-time by Charlie Mulgrew, complemented his quiet menace with a trademark goal.

Wanyama was strong and unshakeable and even had scope to perform an outrageous dribble in the second half. But the battle honours were claimed by Commons even if a hat trick could not in all conscience be awarded to him.

The goal that began this rout started with a Commons shot but the deflection off Liam Craig was so grotesque that the goal has to be awarded to the St Johnstone player. Commons, however, was certainly the scorer of the second when, from a similar position, he drilled the ball past Alan Mannus who had already fended away two shots from the edge of the area from the winger.

The third goal was created by a clever Emilio Izaguirre touch – further evidence that the Honduran is returning to form – and a smart Commons cross that was converted routinely by Hooper.

St Johnstone replaced the ineffective Rowan Vine with Steven MacLean but the tide of the match was unchecked, though the redoubtable Gregory Tade did cause one moment of anxiety to Kelvin Wilson and could have gone down in the penalty box after an intemperate challenge by the Celtic centre-half. The goals, almost inevitably, occurred at the other end of the park. The powerful and pacy Tony Watt was pulled off the ball by Steven Anderson, drawing a booking for the St Johnstone defender and a penalty for Celtic. Commons, of course, took the ball and smashed it past Mannus.

The fifth goal was indicative of the match. Mulgrew was found in so much space at the back post that he could have been forgiven if he had complained of loneliness. He deliberately switched the ball from his right foot to his favoured left and knocked past Mannus who was now in a position of resignation rather than resistance.

The rest was an exhibition. Lennon could afford to replace a centre-back, Efe Ambrose, with Paddy McCourt, resident maverick, without weakening Celtic. One slaloming run by the Northern Irishman was worthy of a highlights DVD from Ski Sunday and was only stopped by a lunging Chris Millar, who was booked.

The St Johnstone charge of eight games unbeaten thus came to a shuddering halt. There were late, minor acts of defiance, perhaps even impertinence given Celtic's swaggering superiority. A David Robertson shot was deflected wide and Nigel Hasselbaink, a second-half substitute, clipped a post.

But the argument was long over. It was left only to debate whether Commons had scored a hat trick. The match itself was never a meaningful dispute. The actions of the Celtic players were unanswerable but this cup tie may just have been settled by the manager's words on a Sunday afternoon.