Gregory Dupont cuts an inconspicuous figure around Celtic's training centre at Lennoxtown. With his easy manner and youthful features, the 35-year-old Frenchman could easily pass as a player, but would fail to draw even a flicker of acknowledgement from the club's supporters.

Yet he is the man behind the headlines.

After Tuesday night's victory over Benfica in the Champions League, his moniker might be: The man who found Aiden McGeady an extra yard of pace'. Dupont was appointed as the club's head of sports science in the summer and has been credited by McGeady for adding an explosive edge to his game.

The 21-year-old's sumptuous technique has never been in question, but he now combines trickery with a devastating turn of speed.

In a sport where small percentages of improvement can make a world of a difference, McGeady's extra gear has seen him emerge as a European-class performer.

"I do feel far fitter and faster after working with Dupont," McGeady said. "In the past, I relied on skill and trickery. Now I have the confidence to knock the ball past our opponents and use my pace."

Tommy Burns, the Celtic first team coach, has watched McGeady and other players' development under Dupont and is delighted at the Frenchman's impact. "He's the top man in his field, a great personality and has made a huge impact at Celtic," he said.

"He is working on a different level altogether.

He looks at things like diet, aerobic and anaerobic capacities, everything to do with the body's engine.

He can help players out tactically and technically."

Celtic have been heavily involved in the development of sports science techniques for the past four or five years but took their time appointing the man they believed could take them to the next level.

A lengthy recruitment process ended with Dupont being headhunted from French club Lille in the summer.

Dupont was a journeyman goalkeeper with French sides Valenciennes and Dieppe in the mid-nineties. Dieppe hit financial difficulties when Dupont was 24, so he decided to go to the University of Lille.

After completing a sports science degree, he began the practical application of his theories. Seven years at Lille helped him establish his pioneering techniques, which he has now brought to Celtic. Dupont works with the first team as a group and also on an individual basis, while he has a substantial input in the reserves and youth teams.

His remit is to improve strength, endurance, agility, speed, power and the prevention of injuries. "It is very difficult to make a player faster, they say natural speed is in the twitch fibres, but you can make them quicker by helping them to anticipate situations better and giving them more explosive power," added Burns.

"You can see that in Aiden's game this season. He is also still going at the same speed in the last two minutes as in the first two."

Where McGeady used to jink past an opponent and then attempt to beat him again, he now has the confidence to utilise his pace. "It's trying to shape mentalities, to give players the confidence to just go past players," said Burns.

"Before, Aiden would be trying to beat a player two or three times in the same area, but if you do that then there's a greater chance that one of the times it will be taken off you. Now he just does it once and he's away, tearing the heart out of them."

After the Benfica game, Gordon Strachan praised McGeady's commitment to maximising his physical condition. Burns also believes McGeady's approach to self-improvement is helping him to fulfil the potential which he first showed as a teenager in the club's youth ranks.

"There's a real top, top level for him," said Burns. "He's making the right progress.

He's been in the first team for three years now. He had a fantastic start to the season last year and finished well too.

"It is a case of putting all the different aspects of his game together. He knows how important the physical side is. Aiden was a tot up until he was 17, but he went to the gym and started working hard. He's always had the exceptional talent but he has had to add more to it to make it even more potent."

McGeady has not been the only beneficiary of Dupont's methods. "Paul Hartley is a player who has always had great endurance levels and he seems to have developed a new dimension to his game," added Burns.

"Scott Brown is another who is naturally fit, but has also benefited. John Kennedy is one of the greatest success stories of all time, to come back from three years out and play at the same level again. You can see his sharpness improving too."