In the early days of Alain Prost's fledgling career it was John Watson who helped him find his feet in Formula One. How ironic, then, that it was Prost who effectively ended the career of the most successful of all Ulster's F1 drivers.
rost went on to become a four-time World champion, a driver so accomplished and calculating he was christened "The Professor". His story, highlighted by his infamous 'Star Wars' conflict with Ayrton Senna, is told in the latest of a line of acclaimed books by Watson's fellow Ulsterman Maurice Hamilton, radio analyst and former grand prix correspondent of the Guardian and Observer.
Based on extensive interviews with Prost at his home in Switzerland, it details the Frenchman's rise to the peak of F1 through the eyes of those most closely involved including Watson who was his McLaren team-mate in his debut season in 1980.
They still have what Hamilton describes as "a warm friendship" which began when Prost, then the European Formula Three champion and on the shopping list of a number of F1 teams, was persuaded to join McLaren as a replacement for Patrick Tambay at the end of the 1979 season.
Those were difficult days for a McLaren team then being run by American Teddy Mayer. Their M28 Cosworth-powered car and even the up-rated version for 1980 still had serious handling issues. It was Belfast-born Watson who took the young Prost under his wing even, on one occasion, taking him to hospital late at night.
They had been preparing for Kyalami - the South African Grand Prix - when suspension failure sent Prost off the road into a concrete wall. He was unhurt but the following day he hit the same wall, this time after rear suspension failure.
"He got whiplash through the steering wheel and complained of a really sore wrist but the attitude seemed to be 'Oh don't be such a tosser, you'll be all right for the race'," Watson tells the author.
"But later that night I was about to go to my room when Marie-Claude Beaumont (the Renault press officer) came after me and said: 'John, John, Alain is in agony. There is something wrong with his wrist. Can you take him to hospital?'
"There was no one from McLaren around so there was nothing for it but to get into my hire car and go looking for the nearest hospital. We eventually found it and they took Alain away for an x-ray and he re-appeared with his wrist in plaster. He had broken his scaphoid, one of the smallest bones in the wrist and a really nasty one to break.
"When I asked the doctor if he could drive the next day they sort of looked at me and said: 'Impossible, he won't drive for six weeks.' Now it was my job not just to get him back to the hotel but to find The Weiner (Mayer) and break the bad news. Talk about the s*** hitting the fan!"
Prost recalls: "John was like a big brother. He didn't really need to be so helpful because, obviously, I was beginning to make life difficult for him on the track. But he was always there with advice. He never failed to pass on helpful information.
"It was so typical of John to take me to hospital."
It had been a less than stellar season for Watson. He not only suffered a string of retirements but was out-performed by the impressive Prost. But there was no animosity between them.
"Alain had become a friend as well as a team-mate. It was a difficult year for me in the team but I blamed McLaren for that, not Alain. I liked the guy; we had fun together. He was clearly a future World champion but that didn't interfere or have any bearing on our personal friendship," writes Watson.
But Prost was becoming disillusioned with McLaren and concerned about the number of suspension failures with the car. It came to a head at the US Grand Prix at Watkins Glen when another failure sent him into the barriers during practice and he was taken to the medical centre.
Later, Watson asked how Prost was and discovered no one from the team had bothered to go and see him. "I did what any decent person would do and went to the medical centre and there was the little fella lying out on a table a bit battered and beaten.
"The first thing he said was 'John, I tell you, I will never drive a McLaren again. You will be the No.1 driver in 1981 but I'm gone, I'm out.'"
And even with another year of his McLaren contract to run, Prost was indeed gone, bound for Renault. But after two years that relationship broke down, too, resulting in an acrimonious split which would have repercussions for Watson.
Prost left at what was a turning point for McLaren, Ron Dennis taking over from Mayer and bringing in John Barnard to design a new car. It coincided with the best period of Watson's career, including his emotional triumph in the 1981 British Grand Prix and then, the following year, victory in Belgium and his astonishing drive from the back of the grid to win the Detroit Grand Prix.
He took the championship chase down to the final race in Las Vegas where Watson lost out to Keke Rosberg.
Joined in 1982 by two-time World champion Niki Lauda, Watson won US Grand Prix West at Long Beach with another amazing drive from 22nd on the grid and, come the end of the season, he felt he deserved an improved contract. His timing could not have been worse.
Over in France, Prost had fallen out with Renault and, after the South African Grand Prix, the two parted company far from amicably. By chance he met Ron Dennis as they waited for a helicopter ride away from the Kyalami circuit. Dennis suggested: "Why don't you come to McLaren?"
With Watson's contract talks stalled and Renault obliged to pay the final year of Prost's deal, it was a win-win for Dennis. He got a cut-price Prost to pair with Lauda and Watson was out, ending his 151 grands prix career.
The rookie he had helped to settle into Formula One had come back to drive him out.
Alain Prost by Maurice Hamilton is published by Blink Publishing, price £22.75.