Everything seemed so clear cut as the Brazilian Grand Prix kicked off the 1994 FIA Formula One World Championship. Having left McLaren for Williams-Renault, Ayrton Senna would resume his domination of Formula One in the car that, since 1991, had let others challenge and beat him.
He had 41 wins to Alain Prost's record of 51, and now that he had eased Prost out of the Williams seat and F1 altogether it seemed only a matter of races before Senna had claimed a record tally of victories to go with his record tally of pole positions.
But by Imola the end of April, the weekend that would change Formula One, Senna had yet to finish a race. He had spun out of the Brazilian Grand Prix at Interlagos and been taken off in the Pacific Grand Prix in Aida. Michael Schumacher and Benetton-Ford had won both races and suddenly become the pacemakers.
Because it was Imola - where this weekend's Grand Prix will be staged 10 years down the line - the atmosphere was light as free practice unfolded on Friday. Now the season was really going to get underway. It added spice that Senna was going to be the underdog for a while. There would be fascination in watching how he coped with the sort of pressure from Schumacher that he had once himself applied to Prost. Only the week before, the former triple champion, Niki Lauda, had voiced the opinion that Schumacher was already superior to Senna.
After 16 minutes of official qualifying on Friday afternoon, the mood changed with Rubens Barrichello's ugly accident in the very quick Variante Bassa.
As the Brazilian was taken first to the medical centre, and then airlifted to the Maggiore Hospital in Bologna, it became apparent that he had had a miraculous escape. The first person he recognised in the medical centre was Senna.
Later Senna gave a press conference. "Imola is dangerous," he said. "There are quite a few places which are not right as far as safety is concerned. But," he added in a supremely valid point, "there are other circuits like that..."
So why did the drivers accept that? Senna shrugged, an eloquent gesture that indicated that he had more on his mind than yet another fight with authority.
"I am the only world champion left," he said. "And I have opened my big mouth too often. Over the years I have learned that it is better to keep my head down..."
The following day the promising young Austrian, Roland Ratzenberger, was killed in his Simtek after a horrible high-speed accident. He became the first man to die in a Formula One car since Elio de Angelis crashed his Brabham during testing at Paul Ricard in 1986.
All sorts of stories abounded about Senna that weekend, and in time much of his behaviour took on the mystique of legend. Certainly he was under a lot of pressure to claw back some of the 20-point deficit to Schumacher. And certainly he was preoccupied at times as he tried to get the best from an aerodynamically improved Williams FW16.
First there were the accidents of Barrichello and Ratzenberger. Senna felt strongly enough to go down to the Villeneuve corner to see for himself what he might be able to do for the Austrian. The stewards sanctioned him for doing so.
Senna went partly because he had predicted a season of accidents following changes to the aerodynamics. "My fears were borne out in tragic fashion; Roland Ratzenberger, racing in his first season, died after an accident on the fastest part of the track. The day before, Rubens Barrichello hit a fence at high speed," he said.
"I know from my own experience that as a young driver one goes into a race in a totally different way and accepts risks that you shake your head about later. Our problem is, at this moment, there are many young drivers and that increases the danger."
There was also talk about reviving the dormant Grand Prix Drivers' Association to address safety issues. And there were emotional problems in his private life. He had a blazing argument with his younger brother, Leonardo, over his (Ayrton's) girlfriend, the model Adrianne Galisteu. Senna called her and said that he did not want to race, but was calmer when he called her later that evening, and seemed himself once more.
During the race morning warm-up session he sent a greeting on air to his old enemy Prost, now commentating for French TF1 television. "A special hello to my dear friend Alain - we all miss you," he said, and the words were affectionate, not sarcastic.
Unbeknown to anyone else, Senna asked the chief engineer, David Brown, to place something in the cockpit of his Williams. It was a furled Austrian flag, which he intended to wave in victory as his tribute to Ratzenberger.
The atmosphere was electric at the start, with Senna on his 61st pole position just ahead of Schumacher. But JJ Lehto's Benetton Ford stalled and he was hit by Pedro Lamy. One of the Lotus's wheels was thrown into the crowd, injuring a policeman. The race should have been stopped while the track was cleaned, but instead because of the god of television it continued behind an Opel safety car that barely had the speed to stay ahead as the pack ran at half throttle.
Senna had led Schumacher round the opening lap, followed by Berger, Hill, Frentzen, Hakkinen, Larini, Wendlinger, Katayama and Brundle. As they went into their sixth lap Senna and Schumacher were finally allowed to start racing again. On their seventh, as they went through Tamburello, the Williams simply did not make the corner but ran inexorably wider until it was off the road and smashing hard into the unyielding concrete wall that had always drawn such criticism. As the car impacted it exploded into a shower of debris before bouncing back into the path of oncoming vehicles.
After agonising hours of uncertainty, the world would learn that Ayrton Senna was dead.
The atmosphere remained electric when the race was restarted. Everybody was keyed up, as if expecting yet another disaster. It came when Michele Alboreto's Minardi lost a wheel in the pits on lap 49.
Many felt the doomed contest should have been abandoned there and then. But the San Marino Grand Prix ground on to its bitter end. And there, on the television screen, all emotion laid bare for an entire world to assimilate, was the cruel truth behind motorsport, the raw meaning behind the ticket warnings that say those simple words: "Motor racing is dangerous".
No one who was at Imola that weekend fails to carry something of it with them. That evening the paddock was silent, full of shattered, stunned people trying to come to terms with the enormity of the weekend when God turned his back.
Senna's old Formula Three sparring partner, Martin Brundle, then driving for McLaren, spoke for many. "I still didn't actually quite believe it all. I still sometimes have to pinch myself to believe that it actually happened, that whole day, that whole weekend."
SENNA'S DEATH: POSSIBLE EXPLANATIONS
Why did Ayrton Senna die? Endless speculation remains as to the cause of his accident Here are some of the main theories:
Broken steering column
After the accident the steering column of Senna's Williams FW16 was found to be twisted and broken, like a pretzel. In the official hearing much was made of this. Senna had asked the team to cut and reweld the column that weekend to shorten it and give him more of a stretched-arms posture.
The former champion Keke Rosberg held to that theory. "Ayrton braked immediately he knew he was in trouble," the Finn said. "The only reason a driver would do that rather than try to fight his way out trouble was if one thing, the thing he held in his hands, told him he no longer had any chance of retaining or regaining control."
Power steering failure
On the Tuesday after the race Senna's team-mate Damon Hill called this writer asking him what he knew about the possible cause. During the conversation Hill revealed that he had been told nothing by the team, except that it was going to disconnect his car's power steering.
Tyre failure was an obvious suspicion, but inspection of the car confirmed that all four tyres were still inflated.
The other thing that most concerned Hill was the effect of slow running behind the safety car. This reduced tyre temperatures which in turn reduced tyre circumference and therefore the critical ride heights of the cars - the distance of the chassis from the track. Until the tyres reached operating temperature this increased the risk that if the chassis grounded over a bump it might toboggan over a series of them. Tamburello was notoriously bumpy, though not particularly challenging.
And the most likely...
Besides the steering-column failure, the most likely cause was that Senna pushed too hard too soon and didn't get away with it when the Williams was thrown off its trajectory when it grounded over the bumps.
The cause of death was massive head injuries. The right front wheel was thrown back into the cockpit inflicting the fatal wounds.