At the Yas Marina season finale, Lewis Hamilton was looking certain to win an eighth world championship until a late crash by Williams driver Nicholas Latifi threw a spanner in the works.
Max Verstappen, Red Bull Racing RB16B, battles with Lewis Hamilton, Mercedes W12, on the opening lap
With five laps to go F1 race control quickly decided to send out the safety car, which put Hamilton in an impossible position, either having to continue on worn hard tyres or cede track position to title rival Verstappen.
Mercedes chose the former, with Verstappen getting a free pitstop for fresh rubber behind.
As the laps counted down race control initially decided not to let the lapped cars between leader Hamilton and Verstappen through, which would have hampered Verstappen's chances of passing Hamilton for the win and the championship, nor did it decide to red flag the race, which it has also done on previous occasions.
But at the last moment race control made a halfway U-turn, deciding to let the cars in between the two rivals unlap themselves yet keep everyone else in position.
The race restarted with one lap left to run and Verstappen inevitably pounced immediately at the hairpin, with Hamilton powerless to resist the Dutchman taking his first world championship with Red Bull.
The late but crucial decision to get the lapped cars out of the way angered Mercedes chief Toto Wolff, who shouted "this is not right" to FIA race director Michael Masi with Masi replying: "Toto, it's called a motor race."
On Twitter Hamilton's future teammate Russell, who had retired from the race early, labelled the conclusion "unacceptable".
"This is unacceptable," Russell tweeted in all caps.
"Max is an absolutely fantastic driver who has had an incredible season and I have nothing but huge respect for him, but what just happened is absolutely unacceptable. I cannot believe what we've just seen."
Despite the chaotic conclusion, a late safety car was the only way Verstappen would be able to come back into play against Hamilton's superior Mercedes pace.
The Brackley outfit's decision not to bring in Hamilton under a previous virtual safety car left it exposed to the type of scenario that unfolded at the end of the race.