Both, clearly, had talent, both were confident and personable. If anything, McNish had the slight advantage, literally, in that he was the smaller of the two and big men are not appreciated by car designers.
On Sunday, however, Coulthard, a day before his 24th birthday, will begin his first full season in Formula One, driving a Williams-Renault, perhaps the best car out there. McNish, 25, will break from preparations for a return to International Formula 3000, the sport's Second Division, and watch proceedings at Interlagos with tangled emotions.
After four years in a kind of motor racing quarantine, McNish has decided he must go backward before he can go forward again. Broken dreams and broken promises have left his confidence in pieces too. Test contracts with McLaren and Benetton came to nothing, as did so many Formula 3000 plans.
"I look at David and see the irony of the situation," McNish said, "but I can't get negative about it. It is a fact. I was always a year ahead of him, now he's in Formula One with Williams, a drive I would like, no question.
"But David's progress and that of a lot of other young drivers coming into Formula One gives me encouragement. It means more team managers are figuring that younger drivers can do the job as well as older drivers, that they are more enthusiastic, have long-term prospects and cost less.
"David surprised me in some respects how well he coped with all the pressures of getting into Ayrton Senna's car last year. But I was not really surprised about the way the season went for him after that. I think this year is going to be harder for him.
"If I didn't believe I could do what David's doing, and even do it better, I wouldn't be here. I am not sour having to do Formula 3000 while he's in a Williams. I've got to be back in the frame in Formula 3000 for people to restore the confidence in me that they might have lost in the past. I had to get back to racing.
"There are a lot of reasons why my career stalled and didn't progress to Formula One, but I do think this opportunity gives me the best way of getting back into it."
His opportunity is with Paul Stewart Racing, the Milton Keynes based team which benefits from more than the merely paternal interest of Jackie Stewart. The three-times world champion was one of those who counselled McNish after an accident he was involved in killed a spectator at Donington, five years ago. Many take the view that the tragedy has undermined McNish's career ever since.
He said: "I think the accident had a lot more effect than was initially realised, a delayed effect. I had a lot of barriers to get over after that. A lot of people were very helpful. Jackie, Ron Dennis and James Hunt were three that come to mind. I don't think you can ever forget it and I don't think you should ever forget it.
"You just have to try to understand how and why these things happen. They tried to reassure me about the whole situation. But it was hard.
"If a driver, for whatever reason, stops doing well, then people think he's finished and there's always another flavour of the month. I haven't driven competitively for a couple of years but Jackie and Paul feel I have the competitiveness still to do the job when others may not have thought that. They have instilled confidence back in me and it's confidence that gets a driver that last little bit."
Coulthard, a graduate of the Stewart Academy, admits his elevation above McNish has been difficult to come to terms with. Finding himself guest of honour at an end-of-season dinner, looking down on McNish, was an uncomfortable experience. He said: "My opportunity to drive in Formula One came in circumstances that you would never expect or want to happen. To have an opportunity like this in a top team is very unusual. All I could say to Allan was I hoped the opportunities would come to him.
"I really can't work out what has gone wrong for him. I am sure the accident affected him in some way and he's probably still aware of it, but it may just be a case of being in the wrong place at the wrong time, that your face just doesn't fit.
"I think this is the right move for him. He's got a vast amount of experience, and PSR have got the budget. If it doesn't work this year and Allan does not win the championship, then there's something else not right there.
"Getting them to Formula One would be the ideal situation, but you wonder whether it will be possible, because if you miss your chance you go down and you've got to be up again before someone else. No doubt at all, the ability is there. It's whether he gets that chance."
Stewart, the most successful of all Scottish drivers, shares that belief in McNish's ability, yet is aware his latest protg requires more than that.
"I think he's been badly bruised by difficult times - the accident, the disappointments with not having a fully funded season which had been promised and never came," Stewart said.
"After the accident he was like a wee boy who had been beaten up.
"It's been sad for him because he's a real talent, he's got all the experience and knowledge, and he's good with engineers. He's got to regroup. He needs the feeling that people are totally behind him, and that he's going to get a full year of motor racing. That, we will supply.
"It's difficult for me to assess now whether he's better than David. On his way up he did all the right things and was every bit as good as David. But the mental setback he had now has to be remedied."
The rehabilitation started the moment McNish slid into his PSR Reynard- Cosworth. "It was a fantastic feeling," he said. "Like a new start. I have a lot of determination and a lot to prove to myself and other people. The Formula 3000 championship is what we are looking for."
And Formula One? "I'm a racing driver and Formula One is what I've wanted to do for a long, long time and that desire won't go away until I actually do it."Reuse content