The 21-year-old took out his maiden MotoGP victory at the Assen circuit in the Netherlands overnight, in a wet-dry race that culminated in a 12-lap sprint after torrential conditions forced a restart.

Beattie, who claimed second and third world title placings in the 1990s, rubbished the assertion from critics that Miller only won because of the conditions.

"The standard response at the moment - media or general fans - is to say 'he's only done it in the wet'," he said. "There's only been a handful of guys who have won races [this year], whether its wet or dry. Marc Marquez is no dill in the wet. If he could have won that race he would have won it. I know he said he settled for second, but you settle for second when you can't win it."

Following the two-second victory, the Queenslander said he was struggling to know what to feel, but made sure to thank Honda for "taking this risk on me".

"A lot of people have bad-mouthed us and said that this project wouldn't work," Miller said. "I just hope we've showed them wrong, and I can ride the bike, and I'm not an idiot."

Beattie, who is now involved with motorsport coverage in Australia, said pressure would have been weighing on the first-time winner.

"No matter who you are, you've always got that expectation, that weight on your shoulders - that people think you should be doing better," he said. "You learn to filter out the stuff that you know is not true and deal with the stuff that is, and he's dealing with the team internally. I think last night, more than anything, was just nice, emotionally, for him to go 'you know what? I can do it. I know it was wet, not dry, but I can do it'."

Miller has forged his own path to the big time, said Beattie, noting his ability to take advice from many sources, but to separate the useful from the unhelpful.

"A lot of times you'll get enormous amounts of advice back - 15 per cent of that is good advice, the rest is garbage," he said. "He's training properly and harder for the big bikes.

"You can see in his face on the podium, he's skinnier, he's more drawn. You can see that he's working out.

"I think he realises now that he's not only a racer, he's got an image that he's got to uphold as a Honda ambassador and the Japanese take that quite seriously."

Injury is the first and foremost stumbling block for Miller's future, according to Beattie, but he said the hardest work is yet to come.

"A mate of mine said to me just recently, 'You think the work is before you get to the top, but the work starts when you get to the top'. That's when the hard work will start for him, when he's actually at the top and trying to maintain that. He's on the right track."