Ninth place or better at the Mexico City Grand Prix makes Kimi Antonelli champion whatever anyone else does, and the Austin race report sets out the two results that would stop him. Below him, nothing is close to settled. On the FIA's championship points document after round 18, George Russell is second on 242 points, Lewis Hamilton third on 241, Max Verstappen fourth on 236 and Charles Leclerc fifth on 233.
Start with what is left to score. Formula 1's weekend pages for Mexico City, São Paulo, Las Vegas, Qatar and Abu Dhabi each list three practice sessions, qualifying and the race, and no Sprint. Five Grands Prix at 25 points for a win leave 125 for any one driver. A driver can still finish above Russell if his total plus 125 passes 242. Lando Norris, on 211, clears that with room; Oscar Piastri, on 144, has a ceiling of 269. Isack Hadjar, eighth on 105, tops out at 230 and is the highest-placed driver already ruled out.
Six drivers behind Antonelli can still finish second, and four of them are covered by nine points, less than a fifth place earns. Ferrari holds two of the four. Hamilton needs to outscore Russell by two points on Sunday to pass him outright, which any finish ahead of Russell does with two exceptions: ninth to Russell's tenth, or tenth with Russell outside the points, would leave them level on 242. Verstappen needs seven points more than Russell and Leclerc ten. Norris, 31 behind, needs more than one weekend.
Sunday can also shorten the list. With four rounds and 100 points left after Mexico City, Piastri's ceiling becomes 244 plus whatever he scores there, so he is out of the running for second if Russell outscores him by three points or more. Norris cannot be ruled out on Sunday: even if Russell wins and Norris scores nothing, Norris would still have 311 points within reach against Russell's 267.
Russell starts his weekend an hour short. Crash.net reports that Mercedes reserve Frederik Vesti will drive his car in Friday's first practice, quoting deputy technical director Simone Resta: "he's going to be sitting in George's car for FP1." The session is owed, not optional. The count of rookie practice runs found that Russell's car had never carried a rookie, and the rules count runs per car, two each. After Mexico, one of the last four rounds has to take a second practice session away from him.
Vesti is one of several stand-ins for the session. Alpine has put Gabriele Mini in Franco Colapinto's A526 for first practice, the Formula 2 series site reports. The Race lists five more rookie runs for the same hour; until the FIA's FP1 classification is published on Friday, none of them is counted here.
Mercedes' constructors' lead is the other number Sunday will test. The FIA document has Mercedes on 607 and Ferrari on 474, a gap of 133. A team can score at most 43 points at a Grand Prix, a win and second place, so 215 remain over five rounds and 172 after Mexico City. To leave Mexico out of reach on points alone, Mercedes has to stretch the gap past 172, which means outscoring Ferrari by 40 or more on Sunday.
Only two Mercedes results reach that margin: a Mercedes one-two, worth 43, with Ferrari on three points or fewer, or a Mercedes first and third, worth 40, with neither Ferrari in the top ten. Any race in which a Ferrari finishes eighth or better leaves the constructors' title for São Paulo at the earliest.
Further down, Red Bull and McLaren arrive level on 355 points, and whichever outscores the other on Sunday leaves Mexico third. Ferrari's second place is not yet safe either: it leads both by 119, fewer than the 215 still available. Racing Bulls sit fifth on 102, 33 clear of Alpine's 69, with Haas on 30.
One caveat sits outside the circuit. Formula 1's calendar on 28 October still lists Qatar on 29 November and Abu Dhabi on 6 December, with full schedules. RaceFans reported on 26 October that Carlos Sainz had doubted both could go ahead because of the war between Iran and the USA, which had already cost the season its Saudi Arabian round and moved Bahrain's race to Malaysia. No statement from F1 or the FIA has changed either date. If one were dropped before Sunday with no replacement, 100 points would remain against Antonelli's lead of 123, and the drivers' title would be settled without a lap in Mexico.
The race is 71 laps of the 4.304km Autodromo Hermanos Rodriguez on Sunday 1 November. If Antonelli takes ninth or better, São Paulo on 8 November opens a four-round contest for second in which Ferrari has two drivers to Mercedes' one. If he does not, São Paulo is his next chance, and Russell will still owe that second practice session.