Max Verstappen and Lewis Hamilton go into the final race of the season, Sunday's Abu Dhabi Grand Prix, level on points.
It is a remarkable situation that has only happened once before in the sport's 71-year history, when Emerson Fittipaldi and Clay Reggazoni entered the 1974 finale level.
In the modern era it is uncharted territory. The championship went to the final race of the season in 2003, 2006, 2007, 2008, 2010, 2012, 2014 and 2016, but on each occasion there was an outright points leader.
Though both drivers have 369.5 points, Verstappen leads the championship by virtue of the "countback" rule. He has nine victories to Hamilton's eight and will therefore win the championship if he is still level on points with his rival come the end of the race.
Unlike most F1 championship showdowns, the permutations for this one are incredibly simple in most instances -- the driver who finishes ahead of his rival wins the title.
There is only one scenario where Verstappen can still win despite finishing behind Hamilton.
Given the way F1's points are handed out, and his lead on countback, he would still win the title if Hamilton finished 9th and he finished 10th and claimed the bonus point for fastest lap. In that instance, both drivers would score two points.
The bonus point can only be claimed if a driver finishes in the top ten, so if Hamilton was 10th and Verstappen out of the points with fastest lap, Hamilton would win the title.
However, given that the pair have finished one-two at the last five races, these seem like highly unlikely scenarios.
While Verstappen is looking for his first championship, Hamilton is going for an eighth. Doing so would move him clear of Michael Schumacher, who he currently shares first on the all-time list with, as the most successful driver in the history of F1.
The teams battle is less tight. Mercedes leads Red Bull by 28 points with one race and a maximum of 44 points to be won in Abu Dhabi.
Mercedes therefore only needs to score 17 points to claim the championship.
F1's points are handed out to the top ten finishers in the following order: 25, 18, 15, 12, 10, 8, 6, 4, 2, 1. That means the lowest result Mercedes needs is for its drivers to finish fifth and seventh, with one of them claiming the fastest lap, in order to take that title.
Red Bull boss Christian Horner admitted on Sunday: "Constructors [title] we are on the back foot now. We need a miracle to win that."