Juan Manuel Fangio said once that "a really good driver should always know why he has won and why he has lost". Karl Ludvigsen's says that Heinz-Harald Frentzen has not mastered this important lesson. And if he hasn't mastered it by now, he never will.

Heinz-Harald Frentzen - or "Harry-Heinz" as Martin Brundle likes to call him - thought he knew why his Nurburgring challenge failed. "I was able to do quite a few quick laps," he said afterward, "but then had a problem with my rear tyres and could not maintain my good lap times. As I accelerated out of the hairpin on lap 49, the traction control just stopped working, which meant I had excessive wheelspin and that caused me to spin off." While the Schumacher brothers basked in the limelight at one of their two home races, enjoying the enthusiastic support of a sold-out German crowd, it was just another depressing day at the office for their countryman from Monchengladbach, now resident in Monaco.

All too often Harry-Heinz isn't aware of what's happened to him or his car. Take qualifying for San Marino this year, for instance. He felt his prospects were good: "I had so much confidence in my car that it was more important to find a really clean lap instead of waiting for the quickest moment in the dying minutes of this session. Unfortunately, my confidence in the car was not justified as I felt massive understeer on my last attempt. I've got no idea why but I was way behind today's possibilities. It's a shame." His potential was good, he felt - but he didn't know why he hadn't reached it.

Then there was qualifying in Austria. "Please don't ask me what happened today," Frentzen said to his fans. "I have really no idea. This morning my car was fine and now this. Somehow everything went wrong and I just couldn't find my rhythm. The disaster was that we couldn't do anything about it until the end of qualifying. I can just repeat that I have absolutely no idea what happened to the car today." Something happened, he thought, but he wasn't sure what it was.

Qualifying at Monaco was another example. He was robbed of practice time by technical problems. During qualifying, he said, "We changed the setup after three laps and continued the development. Unfortunately, I had just one try at the end. Then I tried too much and had a spin. It is a pity." It was indeed a pity, but Frentzen had spun for a specific reason that was spotted by commentator Martin Brundle. At the turn before the tunnel entry some new paving had been laid down that was clearly less grippy. Most drivers were aware of this and avoided the paving, but Heinz-Harald took a line that crossed it. He didn't seem to realise that this was the reason for his spin.

Before last Sunday's European Grand Prix at the 'Ring, his first after missing the Canadian race following a crash in practice, Frentzen said he had some catching up to do. "I have to admit that having missed two tests due to the accidents," he said on Saturday, "I personally had to keep up with the technical developments of the car. This shows once more how quickly the development progresses in Formula One. By and large, however, we have developed the car into the right direction from yesterday to today. On Sunday, I can finish in the points." Even allowing for the domination of the top places by the three best teams, this proved an unrealistic forecast.

These performances, and Frentzen's comments about them, show a pattern that indicates that his best years as a Grand Prix driver are behind him. My advisor in this matter is none other than Juan Manuel Fangio, who knew a lot about winning and losing. "A really good driver should always know why he has won and why he has lost," said Fangio. In my opinion, Frentzen has not mastered this important lesson. And if he hasn't mastered it by now, he never will.

There's no gainsaying Heinz-Harald's speed. He is a very quick racing driver, as he showed in the lesser Formulae in which he starred before moving to Formula One. He was seen as the equal in speed to the elder Schumacher. But speed alone is not enough to bring results in Grand Prix racing. The Schumacher brothers themselves made this point last weekend. When asked the secret of their success they said, "Talent and discipline." Frentzen has the talent, of that there's no doubt. But does he have the discipline to dig deep into every aspect of his job? To keep up with the technology? To probe until he knows exactly why he has succeeded or failed in each and every instance? His record suggests that he doesn't.

Recently Roger Horton interviewed Paul Stoddart for Atlas F1. Asked whom he would choose as a driver for his European Minardi cars if he were given a choice, Stoddart answered, "If I had a blank piece of paper, there are two or three that are already in Formula One that I rate. I rate Heinz-Harald Frentzen a lot. Heinz needs to be loved, but when he is loved he is a performer." Where will he get more love than at Jordan? Frentzen's contract with the Silverstone-based team will continue through 2002, it was confirmed at the weekend.

Reportedly, Harry-Heinz rejected a jump-ship offer from Toyota. That was a good idea. There won't be much time for loving when that outfit faces the real world of Formula One next year. Frentzen was wise to stay with Jordan; it is the best team he will drive for during the rest of his career. Sooner than he expects, Paul Stoddart may get his wish.