Four kilos and eight mph can make Murray a champion

Can I get Andy Murray to No1 is what everybody wants to know. Here's the truth: I didn't know for sure that Andre Agassi or Andy Roddick would go to No1 when I started coaching them. Nevertheless, here's my 100% coaching principle with Andy Murray or anyone else: I don't talk about numbers; I don't obsess about rankings or results. What I talk about are those specific things we need to do to keep getting better; to get closer to the maximum game out of the player. Do that and the ranking will take care of itself.

So, right off the bat I wanted two things for Andy: four kilos and eight miles per hour. In other words, I wanted Andy to get his weight up to at least 73 kilos and his serve up from 132 mph to 140-plus mph with accuracy and consistency. The second won't happen without the first.

To achieve these goals I've brought in Mark Grabow, a top trainer in the National Basketball Association (Golden State Warriors) to get some muscle on the kid. Along with that we've worked on the serve mechanics - mainly getting more legs into it. I want him accurate with power at 60 to 65% on his first serve. That takes time, but when it happens it'll improve a lot of things.

Here's what I like about Murray a lot. He is driven to play perfect tennis. That's why you see him get so angry at himself on the court. He wants perfection and it drives him crazy when he doesn't produce it. But that's good. I like that. You'll never get close to perfection if you don't hunger to actually play perfect tennis. Andy's got the hunger. He's also got the temper.

Somebody compared Murray's temper tantrums to John McEnroe, but McEnroe got furious at everything - the umpire, the opponent (me, a couple of times), or somebody eating a vanilla ice cream cone up in the stands. Andy mainly gets angry at Andy for not doing it perfect. That's the difference in their tempers.

Sometimes he takes it out on me and starts screaming stuff. No problem. I don't have a glass jaw and know he's just venting out of frustration with himself. During a match if he loses his temper, busts a racket, cracks it - no problem. The problem comes if he's still bitching about it six points later. That's a problem I don't want to see and will address.

I don't mind if there's a blow-up now and then, but overall, match to match to match, I think you'll see Andy more reserved, more in control of himself as he learns to stop fighting himself on the court. He's never going to be a choirboy, but he is going to develop better control of his reactions.

Andy's game has a lot of variety to it. In America I'll see a pitcher in baseball who's great because of one big pitch like a curve or a slider or a fastball. Andy's better than that because he mixes up speeds and spins really well. He's got a really interesting way of playing his game which actually reminds me of a better-looking version of how I used to play. He's able to do lots of different things - slice, come over it, flatten it out, a lot of different looks. He can hit hard, but he beats you with his variety.

In one way he's like Miloslav Mecir, the Big Cat, who walked slow but ran fast. Between points Andy looks slow, but then during a point he's unbelievably quick in getting to the ball, in part because he sees what's happening better than most other players. He's sneaky fast - doesn't look like he's moving, but he gets to the ball. His movement is one of his fantastic assets that people generally don't comprehend.

His return of serve is up there with the best of them - maybe equal to Roger Federer's. Unlike Andre Agassi's service return - an offensive weapon - Andy uses his return to neutralise the big serve. Then he works to take charge of the point. Federer and Lleyton Hewitt are like that, too.

One of the reasons Andy is so great at returning serve - neutralising the big one - is because of his wingspan. Andre kiddingly calls him "Extendo-arms" because he can reach so far and fast. It's one of the assets that brought him his first tour victory since we started working together. He beat Ivo Karlovic in the finals of the SAP tournament in San Jose, California even though the 6ft 10in Croat has a monster serve. Andy neutralised it, then took over the point enough times to win.

Also, the thing I find intriguing about his game for such a young age - 19 when we started working together - is that he's really analytical. Andy's a very good thinker for being so young. During our practices he's always pestering me about why I want him to do this drill or that drill. He's always asking "What's the point here? What are you trying to do?" It's like talking to my son Zach, who's about the same age and also questions everything I tell him to do. Andy would drive me nuts, except I'm used to it from Zach.

Andy's liabilities? Well, first I have to say that Andy's got a world-class backhand - big time. But, we'll get it even better. Nothing is ever as good as it can get. Even Federer, who has raised the bar ridiculously high, keeps getting better each year. That's the key: keep getting better and better.

So with Andy we'll take the bar higher on the backhand, but also we'll get him coming to the net more as soon as that serve improves. Great hands like he's got deserve to be at the net more often. We're adding a little kick and little more spin on the serve along with the speed. The forehand can improve.

Overall, though, I'm not looking at radical change. Just some tinkering here and there. For Andy, radical change is that eight miles per hour on his first serve. That is going to change a lot of things for him. For that to happen he needs that extra muscle I mentioned.

One of the differences in the ATP Tour that Andy's looking at that Andre didn't face is this: only Pete Sampras was a realistic challenger to Agassi for the No1 ranking. For Andy he's got five real serious challengers who are about his age: Gasquet, Djokovic, Baghdatis, Berdych, and Nadal. Plus he's got Blake and Roddick and some other strong ones who are a few years older and playing great. And, of course, there's that guy on top: Roger Federer, maybe the greatest tennis player ever. We've got a really strong and deep field on the men's tour - maybe the strongest of all time.

That's why I don't get all worried about the numbers. You look at all those names and all that talent and you might get discouraged. Instead, I just want to keep Andy focused on Andy - getting better and better. Will that be good enough to take over No1? Well, honestly, I wouldn't be doing it if I didn't hope so.

My job is simple, the goal is clear: I am being paid to teach Andy Murray how to become the maximum tennis player he can be. That's a job I like. When I was at ESPN people said I had the best job in the world - travelling around the globe and watching and analysing great tennis matches. No sweat. It was like being paid for talking on the telephone. In a sense, they were right. I had a great job on TV.

But something was missing for me, namely nerves. Maybe there's something twisted in my personality because I like being nervous; the kind of nervous you get on the day of a match. ESPN didn't make me nervous.

Now, when Andy is scheduled to play I wake up at 4.30 in the morning and have a little knot in my stomach thinking about the match. I'll get upset about something I should have done in practice the day before or what I'm telling Andy about the upcoming opponent. Coaching creates nerves. I like that. I guess I'm neurotic.

For Andy Murray or any other player I coach there isn't some magic pill I can give them to win matches. It comes down to their own dedication and hard work. Then their coach surrounds the player with good people and provides good teaching. And, of course, it helps to have some talent. Andy Murray has talent.

He is also a fighter. The great thing about tennis is that it's like boxing in the sense that you go into the ring and it's just you against that other person. One guy tries to pound the other guy out of the ring. It's beautiful because it's so basic. Ultimately, in tennis, you don't have to beat the field. You just have to beat that one guy who's across the net on any particular day - pound him harder than he pounds you.

In Winning Ugly, I teach you how to use it against your opponent. When you are the master of your mind, you will master the art of winning more tennis matches. That's a guarantee. And always remember, it's better to win ugly than to lose pretty.