It took a while, but Christian Horner finally admitted that former FIA race director Michael Mais made a mistake that decided the championship last year in favor of Max Verstappen at the Abu Dhabi GP.

Max Verstappen emerged victorious at the Yas Marina circuit in December after overtaking Lewis Hamilton during what turned into a one-lap "sprint" after a late safety-car period.

Masi decided to allow only the laggards between the two championship protagonists to discount one lap before sending the safety-car into the pits, a decision that defied the regulations by handing the Red Bull driver the title on a platter.

The regulations gave the option for none or all cars to discount a lap, but not just some. If none discounted the lap, five cars would stand between Hamilton and Verstappen on the last lap and it would be almost impossible for Verstappen to overtake all of them and still Hamilton to win the race and the title. If everyone discounted the lap, there would be no time for the race to restart and Hamilton would win both the race and the title.

There were claims that there was a verbal agreement - not provided for in the regulations - that races would not end under the safety car and so Masi would have invented this procedure, but the FIA and the World Motor Racing Council obviously did not accept this claim and Michael Masi was fired.

Horner has defended Masi since the Australian was removed from his post by the FIA before the current season, but speaking at the Cambridge Union, the Red Bull team boss admitted that this mistake was made by the former race director.

"For me, I was very disappointed with the way the FIA dealt with Michael. He was in that race control room doing the best he could with the pressure he had," Horner said.

"The mantra was always very clear that he would always be under pressure to restart the race - 'nobody' wanted to see a world championship won under a safety-car."

"He made a mistake in not allowing all the cars to discount the lap. So I think three cars were at the back of the pack and couldn't do that."

"That was the only mistake he made, so I thought it was tremendously harsh that he was hung, especially in public and the trolling he received and the abuse he received online without any support from the FIA behind him."

"I felt sorry for him, there should have been more support after that championship because he was in an incredibly difficult position."