The 2005 cars have lost some of their aerodynamic efficiency, the engines must last two races rather than one, and each car is limited to just four sets of dry tyres throughout the weekend.

The new tyre regulations in particular have impacted on operational methods on free practice Fridays. It is important that the race drivers, Ralf Schumacher and Jarno Trulli, conserve tyre and engine mileage, so the burden of collating meaningful data to make a race tyre choice falls even more heavily on team test driver Ricardo Zonta.

After the first day's two free practice sessions, West McLaren Mercedes test driver Pedro de la Rosa (1m25.376s) has posted the fastest time, ahead of team race driver Kimi Raikkonen (1m25.676s). New BMW Williams F1 Team driver Nick Heidfeld (1m25.940s) was third quickest, then Red Bull Racing test driver Vitantonio Liuzzi (1m25.967s) and seven times world champion Michael Schumacher (1m26.081s) in the Ferrari. Juan Pablo Montoya's McLaren (1m26.227s) completed the top six.

Zonta's new Toyota TF105 (1m26.808s) finished the day 11th fastest despite being held up on its quickest lap, while Schumacher (1m27.162s) and Trulli (1m27.195s) were 13th and 14th respectively.

"It was a satisfying first day with no technical problems in either session," Schumacher said. "The performance level was better than I expected and I'm looking forward to qualifying already!"

Trulli added: "It's good to finally be back in action and all we could do today was work on balancing the car for the track. However, there is every chance that we could have some rain as the weekend progresses, in which case Saturday will turn into a bit of a lottery for everyone."

The team's Technical Director Chassis, Mike Gascoyne, explained: "A lot of the times look pretty close, so it looks like we are going to get a more exciting year of racing. Running just two sets of tyres with the race drivers makes it pretty difficult. Ricardo, who has unlimited tyres, is obviously in a better position to do performance evaluation and we aim to do that at the end of the first session and then concentrate on a couple of long runs in the second one. It's still quite difficult because of how much the circuit changes and the way of working is certainly quite a bit different. Overall, it all seems pretty tight. McLaren look strong but I think our performance level is very reasonable. If you compare Ricardo with De la Rosa, he wasn't far away at all. In the middle sector they both did very similar times. Ricardo got held up in the first and last sectors but De la Rosa is quicker than anyone and we are less than half a tenth slower in the middle sector, which is highly satisfactory."

Panasonic Toyota Racing had no technical difficulties on the first day of the new season and now looks ahead to the new qualifying format, where single-lap times from sessions on Saturday afternoon and Sunday morning will be aggregated to form the grid for the new seasons' first race.