Mexico City, Mexico - Nico Rosberg wrapped up final Mexican Grand Prix practice by setting the fastest lap for Mercedes on Saturday with triple Formula 1 champion team mate Lewis Hamilton a mere 0.014 of a second slower.
Rosberg, who was alsofastest on Friday (October 30), produced a best lap of 1min:21:083 seconds.
Vettel fourth fastest
Australian Daniel Ricciardo was third on the timesheets for Red Bull with Ferrari's Sebastian Vettel fourth on a sunny morning.
The top four drivers were separated by just two tenths of a second.
Germans Vettel and Rosberg are in a fight for second place in a championship already won by Hamilton who took his 10th victory of the season in Texas last weekend and is equally determined to win the first race in Mexico since 1992.
So apparently our boys were separated by about this much in #FP3... does it cone any closer?! #Groan #F1 #MexicoGP pic.twitter.com/aFcEhg0nRc
— MERCEDES AMG F1 (@MercedesAMGF1) October 31, 2015
Vettel is four points clear of Rosberg with three races remaining. Both have won three times in 2015.
Mercedes have also secured the constructors' title for the second year running but Sunday's race, with more than 100 000 spectators expected, is still important further down the standings as teams chase precious championship points.
Mexico's Perez sixth quickest
Force India's Sergio 'Checo' Perez, the only Mexican in the race, was sixth fastest to the delight of another big crowd at the revamped circuit named after the late Rodriguez brothers who raced in F1.
He slowed down and waved to the crowd as he went through the stadium section at the end of the session.
McLaren's Jenson Button, who faces a 50 place grid penalty due to power unit changes and will start at the back of the grid, recorded the slowest time after doing only a handful of laps due to ongoing problems.
His Spanish team mate Fernando Alonso has a 10 place penalty.
Vettel's team mate Kimi Raikkonen pulled over early in the session with smoke coming from the back of the car.
Raikkonen said: "I have some issue with the engine, vibration at the end of the main straight and I have no power."
3rd free practice session classification
1. Nico Rosberg (Germany) Mercedes - 1min21:083
2. Lewis Hamilton (Britain) Mercedes - 1min21:097
3. Daniel Ricciardo (Australia) Red Bull - 1min21:201
4. Sebastian Vettel (Germany) Ferrari - 1min21:294
5. Daniil Kvyat (Russia) Red Bull - 1min21:530
6. Sergio Perez (Mexico) Force India - 1min21:603
7. Valtteri Bottas (Finland) Williams - 1min21:772
8. Carlos Sainz Jr (Spain) Toro Rosso - 1min21:775
9. Felipe Massa (Brazil) Williams - 1min21:945
10. Nico Hulkenberg (Germany) Force India - 1min22:010
11. Max Verstappen (Netherlands) Toro Rosso - 1min22:039
12. Pastor Maldonado (Venezuela) Lotus - 1min22:042
13. Romain Grosjean (France) Lotus - 1min22:184
14. Marcus Ericsson (Sweden) Sauber - 1min22:871
15. Fernando Alonso (Spain) McLaren 1min23:065
16. Felipe Nasr (Brazil) Sauber - 1min23:067
17. Kimi Raikkonen (Finland) Ferrari 1min24:648
18. Will Stevens (Britain) Marussia - 1min25:654
19. Alexander Rossi (United States) Marussia - 1min28:176
20. Jenson Button (Britain) McLaren 1min29:336