Max Verstappen laid down an early marker ahead of the world championship on the opening day of pre-season F1 testing in Bahrain on Friday while Lewis Hamilton suffered a nightmare start as a sandstorm swept across the Sakhir track.
Verstappen, long regarded as heir apparent to seven-time world champion Hamilton, clocked a best time of 1min 30.674sec in the Red Bull.
The Dutchman also piled up an eye-watering 139 laps.
"We had a very positive day and managed a lot of laps even though the track conditions were quite difficult," said Verstappen who was third in the championship last year.
"We don't need to talk about pace yet and it isn't really a discussion until we get to Q3 at the first race weekend - it's only then you see the real pace in all the cars."
In stark comparison, Hamilton was only 10th fastest in 1:32.912 although his 42 laps dwarfed the six managed by Mercedes teammate Valtteri Bottas, the slowest man on the track in 1:36.850.
Bottas, runner-up to Hamilton in the 2020 championship, even finished behind Haas rookies Nikita Mazepin and Mick Schumacher.
"It was not a good start," admitted Mercedes team boss Toto Wolff at a mid-day press conference.
"We had a gearbox problem that came out of nowhere which we haven't been able to identify yet."
However, Wolff didn't appear too concerned over his team's struggles with two more days of testing to go over the weekend.
With just three days testing in total compared to six and eight in Barcelona in recent years, Wolff said the brief Gulf visit offers only a "vague picture" of each team's readiness.
The season will start in Bahrain on March 28.
The top three on Friday was filled out by Lando Norris in a McLaren in 1:30.889 and Esteban Ocon who clocked a best of 1:31.146 from 129 laps for Alpine, the repackaged Renault.
After a humiliating 2020, and their worst season in 40 years, Ferrari saw Carlos Sainz take fifth place with Charles Leclerc in 11th.
Best first day times:
1. Max Verstappen (NED/Red Bull-Honda) 1:30.674 (139 laps), 2. Lando Norris (GBR/McLaren-Mercedes) 1:30.889 (46), 3. Esteban Ocon (FRA/Alpine-Renault) 1:31.146 (129), 4. Lance Stroll (CAN/Aston Martin-Mercedes) 1:31.782 (46), 5. Carlos Sainz (ESP/Ferrari) 1:31.919 (57), 6. Antonio Giovinazzi (ITA/Alfa Romeo-Ferrari) 1:31.945 (68), 7. Daniel Ricciardo (AUS/McLaren-Mercedes) 1:32.203 (45), 8. Pierre Gasly (FRA/Alpha Tauri-Honda) 1:32.231 (74), 9. Yuki Tsunoda (JPN/Alpha Tauri-Honda) 1:32.727 (37), 10. Lewis Hamilton (GBR/Mercedes) 1:32.912 (42), 11. Charles Leclerc (MON/Ferrari) 1:33.242 (59), 12. Kimi Raikkonen (FIN/Alfa Romeo-Ferrari) 1:33.320 (63), 13. Sebastian Vettel (GER/Aston Martin-Mercedes) 1:33.742 (51), 14. Roy Nissany (ISR/Williams-Mercedes) 1:34.789 (83), 15. Nikita Mazepin (RUS/Haas-Ferrari) 1:34.798 (70), 16. Mick Schumacher (GER/Haas-Ferrari) 1:36.127 (15), 17. Valtteri Bottas (FIN/Mercedes) 1:36.850 (6)