Jerez Day Four: There's no stopping Button

Jenson Button's 1:18.871 proved to be unbeatable on the final - and very productive - day of testing at Jerez.

With the sun beating down on the track and little sign of the rain that dominated proceedings at the start of the week, Saturday's action got underway with Kamui Kobayashi the first to take the P1 slot.

However, minutes later the Sauber driver also became the first to bring out the red flags as his C29 ground to a halt right after the chicane.

Once the action was back up and running, Renault's Robert Kubica stormed into the lead with a 1:19.114, the fastest time set at Jerez this year, at least up until Button put in two short three-lap stints.

The first saw the reigning F1 Champ move up to second place behind the Pole while his second stint had him taking the P1 slot with an impressive 1:18.871. That was 0.243s quicker than Kubica's previous best.

Button's attack on the timesheets, though, was brought to a halt when Mark Webber stopped out on track near Turn 4, the second red flag of the day.

Although Red Bull struggled to identify the problem, the team opted changed Webber's Renault engine as a "precautionary" measure.

An impressive four-and-a-half hours of uninterrupted running followed Webber's incident during which many of the drivers concentrating on race simulations and pit stop practices.

Nico Rosberg's Mercedes GP W01 proved to be solid pace over a long distance as the German covered a 19 lap stint with a consistent pace in the mid 1:21s.

Jarno Trulli, on his first outing as a Lotus driver, put in just over 20 laps with an average pace in the 1:26s. "Jarno with no problems. Sticking with long runs to get mileage on the car," reported tech boss Mike Gascoyne.

"First long run pace was good but Jarno reported big rear drop off over last 5 laps. Need to protect the rear tyres more."

Button was charging around in the high 1:22s during his longer runs, matched by Fernando Alonso, who did 30 laps with an average time in the early 1:22s.

However, the action came to a halt when Nico Hulkenberg, who had completed a massive 137 laps at that point, stopped out on the start/finish straight.

The final hour of testing for the week saw Timo Glock improve his best to a 1:22.433. The German, though, managed the fewest laps of all the drivers due to a hydraulic problem that left him stranded in the pits.

And although some of the drivers ventured out for a late dash, only Rosberg was able to beat his previous best while any last minute attempts were brought to a halt by the day's fourth and final red flag, which belonged to Glock.

• Unofficial Times
• 1. J. Button McLaren MP4-25 1:18.871 108 laps
• 2. R. Kubica Renault R30 1:19.114 +0.243 117 laps
• 3. K. Kobayashi Sauber C29 1:19.188 +0.317 117 laps
• 4. V. Liuzzi Force India VJM-03 1:19.650 +0.779 80 laps
• 5. N. Rosberg Mercedes GP W01 1:20.061 +1.190 130 laps
• 6. F. Alonso Ferrari F10 1:20.436 +1.565 137 laps
• 7. J. Alguersuari Toro Rosso STR5 1:21.053 +2.182 139 laps
• 8. M. Webber Red Bull Racing RB6 1:21.194 +2.323 87 laps
• 9. N. Hülkenberg Williams FW32 1:21.919 +3.048 137 laps
• 10. T. Glock Virgin Racing VR-01 1:22.433 +3.562 27 laps
• 11. J. Trulli Lotus F1 T127 1:23.470 +4.599 141 laps

Source: Jerez Day Four: There's no stopping Button - Planet-F1 News from planet-f1.com