Daniel Ricciardo completed his domination of the Formula 1 rookie test in Abu Dhabi, by setting a time 1.3 seconds faster than world champion Sebastian Vettel pole position lap for last Sunday's grand prix.
Driving Mark Webber's Hungarian Grand Prix-winning Red Bull RB6, the Australian was fastest in the morning session before Mercedes driver Sam Bird knocked him off top spot in the afternoon by five thousandths of a second.
Ricciardo reclaimed the top spot shortly after the one hour to go mark before setting his best lap with two minutes to go after a mechanical problem for Yelmer Buurman brought out the red flags with 20 minutes remaining.
Although track conditions are estimated to have improved by up to 1.5 seconds, the Australian's lap was impressive on only his fourth day of testing in F1.
Renault's Jerome D'Ambrosio recovered from a spin earlier in the day, which led to the session briefly being stopped, to set the second-fastest time in the closing stages of the day. After driving for Virgin yesterday afternoon, the Belgian was seven tenths of a second off Ricciardo's pace and four hundredths faster than Mercedes driver Sam Bird.
Gary Paffett was fourth-fastest for McLaren, returning to action for the team for the first time since February in place of junior driver Oliver Turvey. Paffett finished just ahead of Ferrari tester Jules Bianchi, who set some good times today after focusing on development work yesterday.
Sergio Perez was sixth fastest for Sauber on his F1 test debut, pipping Force India driver Paul di Resta, who set his time early in the morning before handing over to Buurman, with his last flying lap.
Pastor Maldonado made his debut for Williams, switching from HRT. He spent the morning doing aerodynamic work but went faster in the afternoon, lapping three quarters of a second off Rubens Barrichello's qualifying time from last Saturday - although his afternoon was interrupted when a sensor warning forced a precautionary shutdown of the engine.
Jean-Eric Vergne completed his second day of running for Scuderia Toro Rosso. He was ninth fastest but missed the second half of the afternoon session as he had to leave early to travel to Macau for this weekend's Formula 3 grand prix. The British F3 champion also lost time in the afternoon when he stopped on track as a result of an engine warning, forcing a precautionary shutdown because of the age of the powerplant. He finished ahead of Buurman.
Davide Valsecchi made his debut in the HRT F110 in the afternoon session, fresh from winning the final GP2 race of the season on the track three days ago. The Italian caused a red flag when he spun while on course to improve his lap-time, but set his best time - two seconds faster than Bruno Senna's qualifying time from Saturday - at the end of the day.
Also making their F1 debuts were GP2 racer Luiz Razia and Josef Kral for Virgin and HRT, along with Bulgarian Vladimir Arabadzhiev for Lotus.
Pos Driver Car Time Laps 1. Daniel Ricciardo Red Bull 1m38.102s 77 2. Jerome D'Ambrosio Renault 1m38.802s 83 3. Sam Bird Mercedes 1m39.220s 82 4. Gary Paffett McLaren 1m39.760s 84 5. Jules Bianchi Ferrari 1m39.916s 93 6. Sergio Perez Sauber 1m40.543s 91 7. Paul di Resta Force India 1m40.901s 27 8. Pastor Maldonado Williams 1m40.944s 81 9. Jean-Eric Vergne Toro Rosso 1m40.974s 61 10. Yelmer Buurman Force India 1m41.178s 67 11. Davide Valsecchi Hispania 1m43.013s 32 12. Luiz Razia Virgin 1m43.525s 70 13. Josef Kral Hispania 1m44.143s 61 14. Rodolfo Gonzalez Lotus 1m44.312s 41 15. Vladimir Arabadzhiev Lotus 1m45.723s 49 All timing unofficial