Mejbri, 20, followed up his brilliant goal against Brighton with an eye-catching performance in the 1-0 win away to Burnley on Saturday and has now delivered another all-action display in beating Crystal Palace in the Carabao Cup. Supporters respond when they see commitment allied to quality and the data backs up the eye test.

At Turf Moor, the Tunisia international covered more ground than any other player on the pitch, running 12.9 kilometres.

No surprise there, perhaps. But Mejbri also ran further than any United player this season. Further than any United player since Ten Hag arrived at the club. Further than any United player since they began collecting these records in 2019.

It has long been a feature of his game. "He has broken records for total distance, all that kind of stuff," said Birmingham City boss John Eustace last season, where Mejbri enjoyed a coming-of-age campaign in the Championship. It was the making of him.

Speaking to the midfielder in February, he explained the transformation in his game and in his mentality. "Since I am in the Championship, I have seen that I need to work on my physical capabilities. It is making me a better player," he told Sky Sports.

There were lows as well as highs during his time on loan at St Andrew's. It was his first full season in senior football, one interrupted by the small matter of a World Cup appearance midway through it. But lessons were clearly learned.

Humility among them.

"Now I understand that every detail is important and you need to work harder," he revealed. "Even if you think you are the best at something, you will find someone who is better than you. That is why you have to work so hard." These traits are staying with him.

"I think that it is part of my game now," he added, referencing that work rate and physicality. "Even if people are more physical than me, it just makes me think that I need to be more aggressive to win the ball. Afterwards, I can show my technical abilities."

There have been glimpses of that ability this past week. As well as his goal at Old Trafford, there was Mejbri's outside-of-the-boot pass to Marcus Rashford late on against Burnley that almost rewarded him with an assist. He was responsible in possession too, completing all but two of his passes in that game.

But it is the off-the-ball work that really stands out. This is a player who epitomises the attitude that Ten Hag is trying to coax from others in the squad and it helps to explain why the Dutch coach praised Mejbri for doing "the perfect job" against Burnley.

He was perpetual motion but his running was targeted, providing the pressing that Ten Hag demands. He closed down straight from the kick-off and registered four more pressures, as defined by the Second Spectrum data, in the second minute alone.

By the end, there had been 104 of them, the most by any player in a Premier League game this season. Factor in his cameo against Brighton and Mejbri is averaging 100 pressures per 90 minutes - the next man on the list is Rasmus Hojlund with 79.

This is the football that Ten Hag wants to see, those famed rules and principles. Mejbri was not jogging either. Second Spectrum log the number of sprinting pressures - those where the presser reaches a sustained speed in excess of 25 kilometres per hour.

He tops that list too.

Speaking to Ten Hag earlier this month, he explained why pressing is so important to him. "To keep a game under control, to dominate an opponent, the pressing has to be right. We want to play proactive football, to play dynamic football. Pressing is a part of it."

This is the football that Ten Hag wants to see. Just not, perhaps, the players with whom he had expected to be trying to do it. United's problems, from matters outside his control to the breakdown of certain relationships, have robbed him of key personnel.

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Injuries persuaded him to deploy Mejbri and Jonny Evans, also outstanding against Burnley, and there is no great expectation among United supporters that either man is likely to represent the long-term solution to the challenges that the club is facing.

But if this youngster bustling around the pitch can evoke something in the crowd, spark something in a squad in need of that spark, he could yet be the unlikely catalyst for a team and a coach in need of anything to transform the trajectory of their season.