Mercedes could walk away from Austin with both of the 2017 championships wrapped up. Below we explain the permutations required for Lewis Hamilton and Mercedes at the Circuit of the Americas.
Drivers' championship
Sebastian Vettel and Ferrari's remarkable run of misfortune at the last three races has all-but-ended the German's hopes of winning a fifth title this year. The odds are firmly stacked in Hamilton's favour and, though it requires another big point swing in the Englishman's favour, the last three races show that's hardly beyond the realms of possibility
Hamilton can only claim the title if he finishes first or second. If he does either of those, the permutations for each are simple:
• If Hamilton wins, he will become world champion if Vettel finishes sixth or lower.
• If Hamilton finishes second, he needs Vettel to finish ninth or lower to wrap up the title.
"Countback" is key in this equation -- as Hamilton has eight wins to Vettel's four, with four races remaining, he will win any head-to-head tie breaker if he out-scores the Ferrari driver in Austin. That means he will be champion if his lead is 75 points or more when the chequered flag drops at COTA -- so he must out-score the German by 16.
Hamilton would appear to be a strong favourite to win in Austin -- of the five races held at the circuit since 2012, he has won four. His 2015 victory also helped him wrap up that season's championship.
If he doesn't win the title in Austin, the championship race will continue to Mexico. He will be able to wrap it up there by finishing ahead of Vettel (in any position) unless the Ferrari driver wins in Austin and Hamilton finishes third or lower, or Vettel outscores the Mercedes driver by 10 points or more.
Constructors' championship
Unlike the drivers' championship, which only swung dramatically in one protagonist's favour recently, the outcome of the teams' title has looked a foregone conclusion for a little while longer. Remarkably, Ferrari has outscored Mercedes at just four of the 16 races so far -- Australia, Bahrain, Monaco and Hungary. Kimi Raikkonen's 99-point deficit to Vettel (and 158 points to Hamilton) hasn't helped the Italian team's chances of a first constructors' crown since 2008.
With a lead of 145 points and 172 left to play for, Mercedes needs to out-score Ferrari by 16 points in Austin to wrap up the title. In essence, as Mercedes has collected 10 wins to its four (therefore meaning the German manufacturer will win any tie-breaker), Ferrari must avoid a having gap of 129 points or more after the U.S. Grand Prix if it wants to keep its minuscule hopes alive.
A fourth world championship for Mercedes would put the team in elite company. Only Ferrari (2000-2004), McLaren (1988-1991), Red Bull (2010-2013) have won four straight -- this year's championship will give Mercedes the chance of matching the first name in that list, as that run was followed by a fifth Ferrari title in 2005.
What's the likely outcome in Austin?
The Circuit of the Americas is a track that suits Mercedes' car on paper, while Hamilton holds the best record at the circuit. If Vettel can stay in contention after this weekend, the good news for him is that Ferrari should be competitive -- if not stronger than Mercedes -- at two of the remaining three rounds, with Mercedes pinpointing Mexico as a venue for potential struggles.
Add a resurgent Red Bull into the mix and that could allow Vettel to keep his title chances alive for a little longer, but it could also hamper his chances further if the Milton Keynes team is quicker than Ferrari but not the reigning world champions. As Singapore and the following two races proved, anything is possible in a sport as technical and dramatic as Formula One but, unless Hamilton goes on some kind of disastrous run, it looks like a fourth world championship will be heading the Briton's way.