Red Bull's Max Verstappen kept Mercedes off the top of the timesheets in final practice for the Mexican Grand Prix on Saturday, with Lewis Hamilton second fastest and championship leader Nico Rosberg fourth.
Verstappen, who retired from the race in Texas last weekend with a gearbox problem, lapped the Autodromo Hermanos Rodriguez circuit with a best time of 1:19.137 seconds on a sunny morning with blue skies.
Triple champion Hamilton, who is 26 points adrift of Mercedes team mate Rosberg with three races remaining, was a mere 0.094 of a second slower but could blame traffic for denying him the top spot.
The Briton has been faster than Rosberg, who can take the title on Sunday if he wins and Hamilton finishes 10th or lower, in every session, with qualifying to follow.
Australian Daniel Ricciardo, Verstappen's team mate, was sandwiched between the two Mercedes title rivals with Williams's Valtteri Bottas fifth and ahead of Ferrari's Sebastian Vettel and Kimi Raikkonen.
Vettel had been fastest in Friday practice, when organisers said 91,243 spectators - more than on some race Sundays elsewhere - turned up to watch.
"It's going to be interesting to see what the picture is today. The tyres are very sensitive," Red Bull principal Christian Horner said before practice started.
"Ferrari looked very competitive on the short runs yesterday but on the long runs it was different. Mercedes turn the engines down a bit on Friday, let's see what happens when they turn them up this afternoon."
Mexican Grand Prix, Autodrome Hermanos Rodriguez - Saturday, Free Practice 3
| POS | NO | DRIVER | CAR | TIME | GAP | LAPS |
| 1 | 33 | Max Verstappen | RED BULL RACING TAG HEUER | 1:19.137 | | 16 |
| 2 | 44 | Lewis Hamilton | MERCEDES | 1:19.231 | +0.094s | 23 |
| 3 | 3 | Daniel Ricciardo | RED BULL RACING TAG HEUER | 1:19.370 | +0.233s | 17 |
| 4 | 6 | Nico Rosberg | MERCEDES | 1:19.618 | +0.481s | 27 |
| 5 | 77 | Valtteri Bottas | WILLIAMS MERCEDES | 1:19.811 | +0.674s | 19 |
| 6 | 5 | Sebastian Vettel | FERRARI | 1:19.937 | +0.800s | 16 |
| 7 | 7 | Kimi Räikkönen | FERRARI | 1:19.994 | +0.857s | 16 |
| 8 | 19 | Felipe Massa | WILLIAMS MERCEDES | 1:19.997 | +0.860s | 22 |
| 9 | 27 | Nico Hulkenberg | FORCE INDIA MERCEDES | 1:20.255 | +1.118s | 21 |
| 10 | 55 | Carlos Sainz | TORO ROSSO FERRARI | 1:20.325 | +1.188s | 22 |
| 11 | 11 | Sergio Perez | FORCE INDIA MERCEDES | 1:20.472 | +1.335s | 20 |
| 12 | 26 | Daniil Kvyat | TORO ROSSO FERRARI | 1:20.586 | +1.449s | 20 |
| 13 | 14 | Fernando Alonso | MCLAREN HONDA | 1:20.600 | +1.463s | 18 |
| 14 | 30 | Jolyon Palmer | RENAULT | 1:20.959 | +1.822s | 18 |
| 15 | 22 | Jenson Button | MCLAREN HONDA | 1:21.152 | +2.015s | 19 |
| 16 | 9 | Marcus Ericsson | SAUBER FERRARI | 1:21.245 | +2.108s | 21 |
| 17 | 21 | Esteban Gutierrez | HAAS FERRARI | 1:21.338 | +2.201s | 16 |
| 18 | 20 | Kevin Magnussen | RENAULT | 1:21.345 | +2.208s | 17 |
| 19 | 8 | Romain Grosjean | HAAS FERRARI | 1:21.601 | +2.464s | 15 |
| 20 | 94 | Pascal Wehrlein | MRT MERCEDES | 1:21.758 | +2.621s | 23 |
| 21 | 31 | Esteban Ocon | MRT MERCEDES | 1:21.921 | +2.784s | 22 |
| 22 | 12 | Felipe Nasr | SAUBER FERRARI | 1:22.354 | +3.217s | 18 |