Fernando Alonso topped the times on the second morning of Pirelli tyre testing in Abu Dhabi, on his first return to action since missing out on a third world title last weekend.
The Ferrari driver set a best time of 1m40.529s, just over three tenths off the time posted by team-mate Felipe Massa during yesterday's running.
It is the first time Alonso has sampled the new-for-2011 Pirelli rubber, and he ended the morning 0.296s faster than world champion Sebastian Vettel.
The Red Bull driver completed 28 laps this morning, and caused a brief red flag when he suffered a second tyre failure. This followed a similar failure yesterday that Pirelli confirmed was caused by the tyre being cut.
Williams driver Rubens Barrichello was third fastest ahead of Force India's Paul di Resta.
The Scot also briefly caused a red flag when he stopped shortly before midday. This was a precaution caused by a sensor reporting that temperatures had got too high, forcing a shutdown to avoid a repeat of yesterday's problem when the exhaust was damaged. However, di Resta soon returned to the track with the team suspecting that the warning was caused by a faulty sensor.
Sauber driver Kamui Kobayashi was sixth fastest. He will hand over to new team-mate Sergio Perez for this afternoon's running, with the team opting not to use ex-Pirelli test driver Nick Heidfeld because of the need to maximise the track time available to its race drivers.
Michael Schumacher, whose 2010 season was blighted by what the team described as a "weak" front tyre that did not suit his style, also had his first taste of Pirellis. He completed 30 laps, although the front-end problem is unlikely to be solved until the 2011 Mercedes hits the track for pre-season testing in February.
Renault's Robert Kubica completed 47 laps and was eighth fastest. The team is likely to complete a large number of laps this afternoon because its running was restricted yesterday by a mechanical problem.
Toro Rosso's Sebastien Buemi and Lotus driver Jarno Trulli also had their first taste of the Pirelli tyres, while Virgin and HRT continued to run Timo Glock and Pastor Maldonado.
Pos Driver Team Time Laps
1. Fernando Alonso Ferrari 1m40.529s 47
2. Sebastian Vettel Red Bull 1m40.825s 28
3. Rubens Barrichello Williams 1m41.294s 52
4. Paul di Resta Force India 1m41.869s 35
5. Oliver Turvey McLaren 1m42.046s 29
6. Kamui Kobayashi Sauber 1m42.110s 43
7. Michael Schumacher Mercedes 1m42.161s 30
8. Robert Kubica Renault 1m42.178s 47
9. Sebastien Buemi Toro Rosso 1m42.399s 46
10. Jarno Trulli Lotus 1m44.839s 44
11. Timo Glock Virgin 1m45.405s 37
12. Pastor Maldonado Hispania 1m45.516s 27