Andy Murray's ability to handle his emotions in the final set was the key to last night's epic triumph over Novak Djokovic.
When Djokovic was coming at him strongly in the third and fourth sets, he was outplaying Murray with his array of baseline bullets. I think there was a real fear that if he lost, what then?
Where would he have gone from there having played so well and having been two sets up? Would he ever win a Grand Slam after such an experience? We all asked such questions, but Andy didn't seem to be aware of any negative energy.
I'd love to know what has been going on behind the scenes because he looked totally different from the figure we have seen previously in similar situations. All that snarling, the self harming and needlessly getting annoyed with himself was suddenly gone.
What you saw was somebody who looked totally relaxed about they were doing, which we hadn't seen in those previous Grand Slam finals.
It looked like he had been talking to a sports psychologist. There was a different look about him throughout the match, but especially when it got to the fifth set and you wondered how he was going to react to the Djokovic recovery.
He was confident, keen and eager to bring it on. I thought that was outstanding. Was that his coach Ivan Lendl's doing, or someone else behind the scenes? There has been some work done there, and it has paid off handsomely.
Djokovic would have beaten anybody in the world in the third and fourth sets. I include Roger Federer and possibly Rafael Nadal. The wind was hurting Djokovic in the first two sets. I didn't like that sickly smile on his face.
He looked almost fatalistic and when he went two sets down, I thought Murray was going to get the job done in three sets. When the wind relented, it was easier for Djokovic to find his range and he was butchering Murray as we entered the fifth set. That is why I feared the worst.
It was amazing that Andy managed to come through, and says so much about his character. It was a slow burner of a match, but some of the tennis in the fourth and fifth sets was the best tennis you will ever have the fortune to witness.
If Djokovic had lost in three sets, people would have said he was immature and couldn't cope with the wind. The manner in which Murray won answered a lot of questions. I think winning gold by overcoming Federer at the Olympic Games helped, but of course he judges himself on the Grand Slams.
All great players judge themselves on the Grand Slams. From the Olympics, winning the US Open was a step up for him. He firmly belongs in the company of the big three now. There is a big four now in tennis, no doubt about that.
It is the ultimate step up. There won't be any more nonsense about him lacking the nerve or ability to live with the best. He will still get all the pressure at Wimbledon, but he will be better equipped to deal with it now he has won his first Grand Slam.
We could also be dangerously near the end of the Rafael Nadal era because of the knee problems. I have been wrong about that before, but I would be concerned about how Rafa's fitness will stand up to the strains and demands.
I think over the next two or three years, the Grand Slams are going to be shared out fairly evenly. Murray going to be in the mix to win more while Djokovic is going to be at the top of the tree for a long time.
Andy Roddick won the US Open and didn't win anything else. I don't think Andy will have that problem. He is a better player than Roddick. How many can he win? I don't think four or five would be beyond him now. He has every chance to be competitive in three of the next four. And if Nadal is not fit, you would not discount him at the French.
Murray is probably inside the top 10 players to play the game. I think the British public how found it difficult to love him, but they have admired him. I've spoken to him a few times, and he is bright. He has learned the PR game too.
Only Andy knows the influence Lendl has had on him. It has not been a negative. His team looks stronger with Lendl in it. These are exciting times for Andy and British tennis which we can all relish.