First, a disclaimer: I have not played competitive rugby for about a decade. I gave up when everyone else grew taller and wider and I was stuck in my mid-teens as (what I think they politely call) a late developer. Formerly a fly-half of absolutely no repute, I often wonder whether I was wrong to give up the sport. And then I bumped into Maro Itoje. Earlier this week, I was one of three intrepid amateurs given a masterclass by one of this country's supreme athletes. The results were predictably horrific. Sportsmail's Daniel Matthews was given the chance to train with Saracens star Maro Itoje The England and Saracens star put Sportsmail through their paces earlier this week His legs are pumping, his face reddening. But still nothing. No movement but the sliding of studs on a browning pitch. Did I say his? I mean mine, of course. Who knew I wouldn't be able to shift a scrum machine carrying England's second-row enforcer? Six inches and nearly eight stone separate me and Maro Itoje - I'll leave it to the perceptive among you to work out in which order. Yet here I was, knees bent, head bowed (not yet in shame), trying with all I might to push. Three seconds was all I had to move Itoje as far as I could. They could have given me three years and the muddy pitch would have sooner resembled the Somme than I would have made any serious ground. Itoje provided a masterclass in how the best teams in the world operate in attack and defence The 24-year-old watches as Sportsmail's Matthews takes part in a one-on-one attacking drill The only breakthrough I could make was behind me, as my boots slipped again and again in the moist ground. Eventually they gave way completely, sending me face-first into the floor. I had exhausted my resources and moved Itoje all of a few inches. Maybe I could have been a World War I general in a former life. But at least it was over, the most humiliating episode in this exercise of inferiority. Itoje, for his part, was a good sport, imparting insightful advice as he continues he recovery from a knee injury suffered during the Six Nations. Tackling, kick chases and clearing out rucks were all on the agenda. The England star is a master jackal - brilliant at getting over the ball and turning defence into attack in an instant. Itoje took Sportsmail through the skills required to clear out opposition players from a ruck Sportsmail reporter Matthews is sent tumbling by one of his fellow pupils during the class But here he explained how to deal with those brave enough to try and touch England and Saracens ball. Don't aim for their back, or their kidneys, he explained. Break their grip on the ball by targeting their arms. Fortunately there was no need for practical demonstrations on this occasion. When it came to tackling, meanwhile, he explained that a defender's main weapon is their legs, rather than their arms. Which is lucky, considering mine are as strong as particularly brittle Twiglets. It is from a solid base that a player can drive back their opponent and, in the words of Itoje, 'win the collision'. Again not much use to me, given I've done fewer squats than he's had bad games. Itoje took Sportsmail through the keys to success in the tackle and at the breakdown That aggressive approach to tackling, coupled with quick line speed, have made defences crucial components of any successful team. See Shaun Edwards' Wales in the Six Nations. So dominant have defences become, in fact, that World Rugby are considering law changes that will free up space for teams to attack. As it stands, teams have to open up the opposition by creating an angle as they receive the ball. As Itoje explained during a simple one-on-one touch-tackling drill, it was no longer sufficient to receive the ball and then think about piercing a defensive line. More useful advice, but another lesson I am unlikely to ever put into practice. It's said form is temporary and class is permanent. But as I lay face down, in the shadow of that same scrum machine, I soon realised that mediocrity doesn't fade over time, either. All rights reserved for this news site dailymail and under his responsibility