McNamara's band make up the words as they go along

Nothing in this need alarm the 28,000-strong United support mobilising to descend on Parkhead for the William Hill Scottish Cup final against St Johnstone tomorrow. There is only one aspect of management where it seems more impressive - cooler, even - to act on impulse rather than on method, and that is when it comes to delivering team talks. United's intelligent young manager, just 40, isn't one for notebooks, whiteboards and PowerPoint displays. When he speaks to his men before kick-off, at half-time and, if necessary, before extra-time he'll draw on nothing more than his own experience, judgment and vocabulary.

"I won't prepare any team talk," he said yesterday, during a prolonged series of interviews at United's cup final press day. "As always, it'll be done on the spur of the moment. I never write anything down. I usually talk some guff at the last minute. It's the same at half-time, when I don't carry a Filofax around with me, writing stuff down. If someone has made a mistake then it should be important enough for me to remember and not have to write it down. If I don't remember it then it's not worth digging somebody up about it.

"Speeches should come from the heart as well as the head. I worked with managers - like Martin O'Neill and Tommy Burns - who could inspire you and make you feel 10-feet tall. I've taken something from every manager but, ultimately, it's all about what the lads do once they cross that line."

When you have as much football knowledge crammed into your brain as McNamara does, it brings a certain confidence when it comes to winging it in a dressing room. He played in five Scottish Cup finals: winning in 2001, 2004 and 2005 with Celtic, losing with them in 2002 and tasting defeat again with Falkirk, late in his career, in 2009. It was in April 2011, that he became a manager. Last season, he steered Partick Thistle to the Challenge Cup final but had left for United by the time of the game, meaning this will be the first cup final of his managerial career. Ivan Golac and Peter Houston are the only men ever to lead United to Scottish Cup wins.

The prospect of joining them awaits McNamara, as does claiming a place in the Europa League and delivering an unforgettable day for the club's largest ever turnout of supporters. Victory would also give him the pleasure of an open-top bus parade through streets of celebrating fans, an occasion denied him as a Celtic player. He has the sense to appreciate rich days like these.

"In football you never know what's round the corner. Danny Lennon won the League Cup for St Mirren and a year later he's out of a job, that's the sad part of football. Football can be savage, either as a manager or a player. You are only important if you are wanted and a part of the picture. It's the same for a manager; if results are not good or things change at the club then you can find yourself out of a job. I am like the players just now. I'm looking forward to it, both excited and nervous and I wish the game would start now."

He was relaxed, calm and good-humoured, making a joke about the fact his old Celtic team-mate, Neil Lennon, had offered their Lennoxtown training ground to St Johnstone manager Tommy Wright rather than him.

"Tommy must be closer to Neil than me," he said, grinning. "I did get offered it before the Rangers game [United's semi-final] but I didn't get offered it before this one!" It was a non-issue in any case, because McNamara had decided that United would adhere as closely as normal to their usual regime. They will train at their St Andrews camp again this morning before travelling to Glasgow. Gary Mackay-Steven an John Souttar are recovering from flu and McNamara will finalise his team when he's sure of their availability.

They will turn up at Parkhead as favourites, albeit facing a team that has had the measure of them this season. United won the first of their four Premiership meetings but St Johnstone took nine points out of nine from the subsequent three. Free-scoring, cavalier United did not manage even one goal against them in those 270 minutes. "Even if we had won four out of four I would still approach this game in the same manner," said McNamara. "I have respect for them and I know how hard a game it is going to be. They are very experienced and organised, they know what they are doing and the midfield works very hard for their defence. They have a good back four but their midfield works hard to help them. At the other side they have the talisman of Stevie May, who has had a terrific season and can score a goal from nothing."

What concerns him is a tendency his players have shown to lose concentration. "It has cost us goals. It happened when we played St Johnstone and in our last few league games, against Aberdeen and Celtic. It comes down to awareness and players doing their job properly. It means speaking to them and just making them aware of the importance of things.

"We all make mistakes. We all make hundreds of mistakes every day. If my players make them doing something positive then I will stand by them. But if they are negative, that's when I will lose my patience."