Sebastian Vettel set the quickest time as Red Bull came to the fore in practice for this weekend's Spanish Grand Prix at Barcelona.
The McLarens of Lewis Hamilton and Jenson Button had set the pace in the day's earlier session, but Red Bull showed firm signs of its expected advantage around the Catalunya circuit once soft tyres were bolted on for runs towards the end of the second 90-minute practice.
Vettel was the only driver to below the 1m20s barrier, setting a best time two tenths of a second faster than team-mate Mark Webber, who sat atop the timesheet for the majority of the session after posting the best time on the hard tyre runs early on.
The pair were, ominously, six tenths clear of the rest of the field. But the pack was tightly packed behind with the next six tenths covering from third to ninth.
Michael Schumacher was the fastest of the challengers, continuing to overshadow Mercedes team-mate Nico Rosberg this weekend with the latter only seventh.
Fernando Alonso finished the session fourth after finding a significant increase in pace on the softer tyre and working his way down to a 1m20.8s.
Hamilton lay second to Webber early on, but only improved by two tenths of a second later in the session while most others were making significant gains on the soft tyre. He ended up fifth with his McLaren team-mate Jenson Button was ninth, but less than two tenths slower.
Robert Kubica was sixth quickest for Renault, ahead of Rosberg and Felipe Massa, with Adrian Sutil completing the top 10 after reclaiming his seat from Paul di Resta.
Pedro de la Rosa did his first running of the weekend after losing the morning practice to a gearbox problem. He completed 37 laps and finished 11th.
Lotus was again the quicker of the new teams, this time with Jarno Trulli leading Heikki Kovalainen. Lucas di Grassi was 21st in his older-spec Virgin, while Timo Glock was only 24th in the new version.
The session's only stoppage came early on when Nico Hulkenberg crashed his Williams. The German ran wide exiting the quick right-hander onto the back straight, but kept his foot in and lost the car on a bump as he tried to rejoin. He spun back across the track and into the wall on the inside, damaging the front and rear of his car and taking no further part in the session.
Elsewhere, Jaime Alguersuari's session was cut slightly short when he stopped out on track with just three minutes of the session remaining.
Pos Driver Team Time Laps 1. Vettel Red Bull-Renault 1:19.965 24 2. Webber Red Bull-Renault 1:20.175 + 0.210 35 3. Schumacher Mercedes 1:20.757 + 0.792 28 4. Alonso Ferrari 1:20.819 + 0.854 30 5. Hamilton McLaren-Mercedes 1:21.191 + 1.226 23 6. Kubica Renault 1:21.202 + 1.237 36 7. Rosberg Mercedes 1:21.271 + 1.306 27 8. Massa Ferrari 1:21.302 + 1.337 25 9. Button McLaren-Mercedes 1:21.364 + 1.399 26 10. Sutil Force India-Mercedes 1:21.518 + 1.553 32 11. de la Rosa Sauber-Ferrari 1:21.672 + 1.707 37 12. Liuzzi Force India-Mercedes 1:21.904 + 1.939 32 13. Kobayashi Sauber-Ferrari 1:21.931 + 1.966 29 14. Buemi Toro Rosso-Ferrari 1:22.184 + 2.219 37 15. Barrichello Williams-Cosworth 1:22.192 + 2.227 33 16. Petrov Renault 1:22.435 + 2.470 35 17. Alguersuari Toro Rosso-Ferrari 1:22.449 + 2.484 34 18. Hulkenberg Williams-Cosworth 1:23.765 + 3.800 7 19. Trulli Lotus-Cosworth 1:24.209 + 4.244 26 20. Kovalainen Lotus-Cosworth 1:24.894 + 4.929 22 21. di Grassi Virgin-Cosworth 1:25.066 + 5.101 30 22. Chandhok HRT-Cosworth 1:25.972 + 6.007 23 23. Senna HRT-Cosworth 1:26.152 + 6.187 25 24. Glock Virgin-Cosworth 1:26.596 + 6.631 21 All Timing Unofficial