Joining Mark for his first day of testing in 2005 was Antonio Pizzonia, who was replacing Nick Heidfeld. Antonio would finish the day over a second behind Mark, after suffering technical difficulties with his car.

For both drivers they continued the development work on components for the FW27. Mark would focus on tyre testing for Michelin, completing seventy two laps. His fastest lap was a 1m:16.437. Antonio focussed on set-ups, completing sixty four laps with a best lap time of 1m:17.675.

For Antonio he again was under the scrutiny of the team as the team continued their evaluation of Antonio and Nick as they work towards making a decision regarding who will join Mark as the second race driver for the team.

WilliamsF1 Test Team Manager Tim Newton commented: "Antonio Pizzonia joined Mark Webber at Jerez today for his first test session of 2005. Unfortunately, however, we experienced a number of technical problems which prohibited Antonio from running at full pace. Mark achieved the quickest time of the session while concentrating on tyre evaluations with Michelin in the interim FW26. Nick Heidfeld will join Antonio tomorrow for the penultimate day of the test.”

Pos Driver Car / Engine Best Laps Tyres

1 M Webber WilliamsF1 BMW 1:16.437 35 / 72 M
2 K Raikkonen McLaren Mercedes 1:16.831 23 / 93 M
3 A Wurz McLaren Mercedes 1:17.133 19 / 95 M
4 F Montagny Renault 1:17.453 4 / 133 M
5 J Button BAR Honda 1:17.510 33 / 93 M
6 A Davidson BAR Honda 1:17.602 66 / 125 M
7 A Pizzonia WilliamsF1 BMW 1:17.675 19 / 64 M
8 M Gené Ferrari 1:18.190 23 / 37 B
9 R Schumacher Toyota 1:18.197 29 / 70 M