Reflecting on the 2012 world championship battle in the latest edition of Red Bull's in-house magazine the Red Bulletin, Marko argued that Alonso got distracted by off-track aspects while Vettel focused solely on driving.
"Sebastian's driving was virtually flawless," said Marko. "But he is a phenomenon: it is always like that.
"After the summer break, his performance curve shoots up. That's what happened in previous years, too.
"I don't know how he does it, but to keep doing it cannot be a coincidence. That brings us back to his method of preparation, the way he shuts himself off from the rest of the world, so that he can still call on reserves that other drivers might not have.
"Fernando Alonso, for example, who is busy with politics and funny comments.
"Vettel ignores it all; he doesn't read the newspapers, or the internet. And that's the point, you see, we concentrate on our job: to make the fastest car and the best team possible."
Marko claimed that Ferrari founder Enzo Ferrari would have been harder on his team in defeat than Alonso and current chiefs.
"I believe that there is no way old Enzo would have liked such defeat, but he would acknowledge the performance of the opposition," he added.
"And then [he] would whip his boys accordingly so they'd do everything to beat us.
"But not with such actions as we have recently experienced. Alonso is constantly involved in politics.
"I believe we saw the stress he was under towards the end of the season. Saying things like, 'I'm competing against [Lewis] Hamilton, not Vettel,' and 'I'm up against [Adrian] Newey,' these psychological skirmishes. We said, 'Just ignore him.'"
Marko says he has little time for critics of Vettel, and is not worried by speculation that his German driver could switch to Ferrari in the future.
"There is a lot of nonsense being said. 'Vettel can't overtake.' Ridiculous; just look at Abu Dhabi and Brazil. 'He is only able to win because he's sitting in a Newey car.' We have two Newey cars, so why aren't we clinching one-two at every race?
"Then the comment of the great Jackie Stewart that Vettel must go to another team to prove himself. This is said by someone who scored all his greatest successes in just one team, Tyrrell. I can't take it seriously."