Raikkonen's solitary walk through the arid landscape in overalls and helmet, before being collected by a scooter, was an arresting sight – if also typical of a driver with 'Iceman' tattooed on his left arm.
The Finn did a mere six laps before stopping with high engine temperatures.
While Raikkonen built up a sweat, Vettel settled in at the top of the timesheets, with his best lap of one minute 32.697 seconds beating the Red Bull of Australian Daniel Ricciardo by a healthy 0.400 margin.
With the dusk-to-night race and qualifying run in cooler conditions, champions Mercedes appeared to be focused more on longer runs with heavier fuel loads as track temperatures hovered around 37 degrees celsius.
Triple world champion Lewis Hamilton, level with Vettel on 43 points after one win and a second place each from the opening two races, was 10th fastest in 1:34.636 while Finnish team-mate Valtteri Bottas was 14th.
The Mercedes pair did more laps than anyone else, however, with Hamilton completing 28 and Bottas 27 compared to Vettel's total of 21.
Mercedes non-executive chairman Niki Lauda spent much of the session chatting to the sport's former commercial supremo Bernie Ecclestone, who was appearing at a race for the first time since he was shuffled aside by chairman Chase Carey and Formula One's new owners Liberty Media.
Red Bull's Max Verstappen was third fastest with Mexican Sergio Perez fourth, followed by the two Williams of Brazilian Felipe Massa, who reported brake problems late in the session, and Canadian teenager Lance Stroll.
German driver Pascal Wehrlein, who missed the first two races with a back injury, returned with Sauber and completed 23 laps in 18th place and only marginally slower than Swedish team mate Marcus Ericsson.
McLaren's Belgian rookie Stoffel Vandoorne stopped on track with engine problems 21 minutes from the end.
FIRST FREE PRACTICE: TIMES
1. Sebastian Vettel (Germany) Ferrari 1:32.697
2. Daniel Ricciardo (Australia) Red Bull – TAG Heuer 1:33.097
3. Max Verstappen (Netherlands) Red Bull – TAG Heuer 1:33.566
4. Sergio Perez (Mexico) Force India – Mercedes 1:34.095
5. Felipe Massa (Brazil) Williams-Mercedes 1:34.246
6. Lance Stroll (Canada) Williams-Mercedes 1:34.322
7. Esteban Ocon (France) Force India – Mercedes 1:34.332
8. Fernando Alonso (Spain) McLaren 1:34.372
9. Romain Grosjean (France) Haas – Ferrari 1:34.564
10. Lewis Hamilton (Britain) Mercedes 1:34.636
11. Daniil Kvyat (Russia) Toro Rosso – Renault 1:34.838
12. Nico Huelkenberg (Germany) Renault 1:34.927
13. Stoffel Vandoorne (Belgium) McLaren 1:34.997
14. Valtteri Bottas (Finland) Mercedes 1:35.002
15. Jolyon Palmer (Britain) Renault 1:35.068
16. Kevin Magnussen (Denmark) Haas – Ferrari 1:35.579
17. Marcus Ericsson (Sweden) Sauber – Ferrari 1:35.888
18. Pascal Wehrlein (Germany) Sauber – Ferrari 1:35.959
19. Carlos Sainz Jr (Spain) Toro Rosso – Renault 1:36.079
20. Kimi Raikkonen (Finland) Ferrari 1:42.333