With 9996 runs on his account, Alastair Cook clipped a leg-stump half-volley for four. It was a stroke born of matter of fact, like the modest celebration that followed. Cook doesn't do theatre, he does real. Ten thousand runs is real: nothing flowery about 10K. I remember the first innings I saw him play exactly as I remember the last, this one. They were barely different. He has become a member of an elite club, amongst whom are devastating strokemakers, stylish accumulators and never-say-die competitors. Twelve men with one thing in common: bloody-mindedness.

Top of the list is Sachin Tendulkar, the most celebrated cricketer in history. For all the attention Australia has accorded Sir Donald Bradman, it doesn't come close to India's love affair with Tendulkar. The other names roll off the same tongue - Ricky Ponting, slayer of foreign armies; Jacques Kallis, cricketer for all seasons; Rahul Dravid, defender of the faith; Kumar Sangakarra, tiger-like fighter for all conditions; Brian Lara, player of the greatest innings; Shiv Chanderpaul, Guyanese sentry; Mahela Jayawardene, beautiful Sinhalese; Allan Border, unshaven warrior; Steve Waugh, true grit; Sunil Gavaskar, Indian master; and now, alongside them, Alastair Cook, England's guardian and her strong upper lip.

At the start of the summer of 2005, I stopped by Lord's to see a young Essex batsman about whom good judges were saying happy things. He played mainly from the crease, blocking good balls with the straightest bat and waiting for short balls that he then flashed to the boundary. He cut powerfully and gleefully - "This is my shot, you fool," he seemed to say - and pulled with near-perfect technique, bringing the bat down on top of the ball's bounce and rolling his wrists at the point of impact. He tucked a couple of stray balls off his pads and ran with vigour between the wickets. That was it really; mainly prosaic. Then I saw Graham Gooch and asked him. He told me that this lad Cook would make a mountain of runs in Test match cricket, which is an un-Gooch-like comment.

Thrice I have seen him emotional on the public stage. First, at the end of that summer of 2014; second, after winning back the Ashes last summer. And then here at Chester-le-Street. Not choked, just proud and a little overwhelmed by the enormity of it all

A few months later, Cook made two hundred for Essex against Australia at Chelmsford. A few months after that he made a hundred on debut for England in India. Next I knew, he was back at Lord's for England twice in the summer of 2006. He made 89 the first time and a hundred the second. He was the youngest Englishman to score a thousand Test runs; and two thousand; and three and four and five. He is, of course, the youngest of the 10K dozen noted above.

I like the story of his scholarship to Bedford School, which came from his gifts as a musician, for he sang like an angel and played the clarinet to grade eight. He was 14 years old when an MCC team arrived a man short to play the school 1st XI. He went to watch with some mates when the master in charge of cricket asked him if he would like to make up the numbers for the visitors. Sure, he said, and made a hundred. By the time he left, aged 18, he had made 19 hundreds for the school. The music master was forever pleased with himself.

There are many things about Cook that surprise, such as his high level of fitness. At the national sports centre, he rates alongside the rugby players and other athletes. He wins anything to do with stamina in the England dressing room. When he made 235 not out in Brisbane, a hothouse of humidity - and by saving the match set up the Ashes success in 2010-11- he left the field with barely a bead on his brow. In the next Test, in Adelaide, he made another hundred, thus matching Bradman in scoring 15 hundreds before his 26th birthday. I could go on.

Above all things in the Cook canon are concentration and patience. He can look a bowler in the eye, knowing that it is not he who must turn away to bowl again. To their frustration he rations himself, offering no obvious weakness and no characteristic upon which they can hang an angry hat. He just blocks and leaves; cuts, pulls and works the ball from his body. Gooch has been his mentor and friend, and all that Gooch learned, much of it from Geoffrey Boycott, has been passed on.

He is a stubborn so-and-so and naturally wary. Part of this comes from his own reticence in front of camera, or behind a microphone; the rest of it from his feeling that those in glass houses (press boxes and commentary boxes) should be more careful with the stones they throw. He believes that modern cricket is the equal of, or has improved upon, any other era in the game's history - an argument over which he cannot be swayed. He may be right, of course, but it is the one area in which he and his mentor do not see eye to eye.

He was badly stung by the heavy criticism that followed the 5-0 thrashing in Australia in 2013-14, the short series loss to Sri Lanka at the start of the English summer and the loss to India at Lord's that left England 1-0 down with three to play. Retreating into darkness, he began to wonder if, a) the job of captain was for him, and b) he wanted it anyway. Runs were suddenly hard to find, field placements were driven by damage limitation and bowling changes by rotation. His confidence had gone. The calls for his head bounced around the land. He refused to hear them and came to two conclusions: a) he badly wanted the job, and b) he was the man to whom this group of players would best respond. He made 95 and an unbeaten 70 in the third Test against India, which England won. Then his regenerated team thumped them at Old Trafford and thumped them at The Oval too. Fantastic. Captain Cook was back, stronger even than before and pleased to have shoved it down the throat of the naysayers.

Thrice I have seen him emotional on the public stage. First, at the end of that summer of 2014; second, after winning back the Ashes last summer. And then here at Chester-le-Street. Not choked, just proud and a little overwhelmed by the enormity of it all. He did agree that it was pretty cool but refused to linger on such a personal thing. He turned instead to James Anderson's 450th wicket and match-winning effort on a dead flat pitch. Well, he would.

What do I say, 10,000 runs on, about the man I first saw at Lord's 11 years ago? I say that few sportsmen have brought such integrity to their performance and such dignity to their game. I say that cricket is as lucky to have Alastair Cook as Cook is lucky to have cricket. And I'd say his life will remain happy because of the selfless parameters in which he lives it. And I'd add that there is plenty of petrol left in the tank, a line Gooch used to like.

Mark Nicholas, the former Hampshire captain, presents the cricket on Channel Nine in Australia and Channel 5 in the UK