The boy puts the whistle to his lips... but not a sound emerges. And as the match rages around him, no one realises that the young referee has blown for a foul. Nerves have trumped his attempted display of authority.
It's the most common beginners' mistake, explains Steven McLean, a professional referee and the man behind a course in Scotland designed to pass on refereeing skills to schoolchildren. (In a recent personal highlight, he officiated behind the goal at Milan's San Siro stadium when AC Milan played Barcelona in the Champions League.)
The Scottish Football Association award allows school students to become fully qualified referees - but the broader aim is to pass on skills and qualities that they can carry into all aspects of their lives.
Children find themselves overwhelmed in the role of referee, so in the early days, when a foul is committed all 22 players stop and look expectantly at the rookie ref. But, Mr McLean explains, the student is still feeling like a spectator and has simply forgotten to whistle.
He says the real hope is to develop the students as individuals - to benefit them as a person. "That's certainly the huge attraction from the schools' point of view," he says.
"A referee must show leadership, manage people, defuse confrontations, be ultra organised, cope with extreme pressure, solve problems and make judgements in a split second."
The 40-hour course is divided into two units: Laws of the Game and Practical Refereeing. The first part is classroom-based and factual. Unit 2 gets students out of the classroom - for fitness tests, pitch inspections and the first chance to referee a match.
Norrie Pattison, a PE teacher at Bannerman High in Glasgow's east end, chuckles as he recalls one boy despairing at the dryness of Unit 1, saying: "Oh my God - do we need to know what the pressure of the ball is?"
But he says the new knowledge soon infiltrated Monday-morning discussions of the weekend's football - resulting in fewer "Did you see that goal?" comments and more "Could you believe that red card?" The recent Luis Suarez biting incident sparked a particularly energetic discussion. "It's like a football phone-in," says Mr Pattison, whose school has had 28 boys (but no girls) of all abilities taking part in the course.
He says it's been particularly good for those students who count down the days until they leave school. Extracting education from football, the great obsession of young Scottish men, he says, has reenergised them.
"It's given a boost to children who were maybe just drifting towards the end of term - a focus. And it's very good for self-esteem. One boy changed dramatically from being very quiet to someone who had an opinion and was able to transfer that into his other subjects."
There are 18 schools and two colleges running the course - from those in leafy suburbs to others in deprived inner-city areas. When it started last year, 136 students signed up, 79 passed Unit 1 and 49 went on to pass Unit 2, securing eight Scottish Credit and Qualifications Framework credit points at level 7 - a quarter of an Advanced Higher. Some 344 school and college students signed up this year, but Steven McLean hopes that more girls will apply for the course. Only 12 took it last year, and just 100 of Scotland's 3,200 fully qualified referees are women.
Refereeing is more than a desultory list of skills - it can sometimes seem like a state of mind. The best referees have the forbearance of Zen masters; they are beacons of impassive calm in the maelstrom around them. But attempting to project such self-assuredness can seem daunting - particularly for self-conscious adolescents. Some students are so shy that when they first blow a whistle, they barely produce a sound.
But more than just boosting the number of referees, Mr McLean wants the course to change attitudes. Referees are a lightning rod for pent-up aggression that would otherwise be socially unacceptable. Scottish referees' sponsorship by Specsavers - which pays for schools and colleges to run the course - is a wry nod to that disdain. "We are looking for a cultural change," he says. "We hope that the fans, managers and players of tomorrow will have a better understanding of the role.'
Back at Bannerman High, Mr Pattison says he has seen attitudes towards referees change among his students: "I think they've got a lot more respect for them. There's a greater understanding of the pressures - they don't question referees' decisions."
Mr Pattison recalls refereeing a game involving his school in which a Bannerman player questioned his decision to award a foul. But another player, who had taken the refereeing course, calmly explained why it was the right decision. His unexpected intervention, and his rational explanation, left Mr Pattison "gobsmacked".
Scott MacPherson, 17, says he no longer finds himself berating referees when watching his team, Partick Thistle, after taking the course. 'I combined the course with football coaching and I think the confidence I gained from the course has made me a better coach," he says.
"I don't think I have the ability to be a professional footballer - but I might make it as a referee."