Fernando Alonso pushed his revised Ferrari to the top spot during the first free practice session of the 2012 Spanish Grand Prix weekend.
The Spaniard’s time came an hour into the session, knocking World Champion Sebastian Vettel’s Red Bull to second.
Kamui Kobayashi posted the 3rd fastest time, ahead of McLaren’s Jenson Button in 4th.
McLaren were testing new parts in Barcelona; the team ditched the low nose it introduced at the start of the season for a new more conventional one.
Valtteri Bottas, Williams’ reserve driver, drove Bruno Senna’s car to 5th, with seven time world champion Michael Schumacher a close 6th.
Romain Grosjean put his Lotus in the top 10 as he clocked the 7th fastest time, followed by McLaren’s Lewis Hamilton in 8th.
Kimi Raikkonen and Nico Hulkenberg were 9th and 10th respectively.
1. Fernando Alonso Ferrari 1m24.430 2. Sebastian Vettel Red Bull-Renault 1m24.808s + 0.378 3. Kamui Kobayashi Sauber-Ferrari 1m24.912s + 0.482 4. Jenson Button McLaren-Mercedes 1m24.996s + 0.566 5. Valtteri Bottas Williams-Renault 1m25.120s + 0.690 6. Michael Schumacher Mercedes 1m25.187s + 0.757 7. Romain Grosjean Lotus-Renault 1m25.217s + 0.787 8. Lewis Hamilton McLaren-Mercedes 1m25.252s + 0.822 9. Kimi Raikkonen Lotus-Renault 1m25.285s + 0.855 10. Nico Hulkenberg Force India-Mercedes 1m25.339s + 0.909 11. Jean-Eric Vergne Toro Rosso-Ferrari 1m25.367s + 0.937 12. Felipe Massa Ferrari 1m25.433s + 1.003 13. Mark Webber Red Bull-Renault 1m25.539s + 1.109 14. Nico Rosberg Mercedes 1m25.607s + 1.177 15. Sergio Perez Sauber-Ferrari 1m25.918s + 1.488 16. Daniel Ricciardo Toro Rosso-Ferrari 1m26.226s + 1.796 17. Pastor Maldonado Williams-Renault 1m26.297s + 1.867 18. Paul di Resta Force India-Mercedes 1m26.630s + 2.200 19. Vitaly Petrov Caterham-Renault 1m27.475s + 3.045 20. Timo Glock Marussia-Cosworth 1m28.267s + 3.837 21. Alexander Rossi Caterham-Renault 1m28.448s + 4.018 22. Charles Pic Marussia-Cosworth 1m28.633s + 4.203 23. Pedro de la Rosa HRT-Cosworth 1m29.107s + 4.677 24. Dani Clos HRT-Cosworth 1m31.618s + 7.188