Heidfeld beats Pizzonia to seat

The German, who spent the winter being evalutated alongside Williams' regular stand-in Pizzonia, was picked following a final shoot-out between the two during testing at Valencia last Wednesday. Heidfeld is believed not only to have impressed Williams with his speed but also his technical feedback.

"It's a big chance for me," said Heidfeld. "My goal has always been to win the world championship. When that will be we will see."

It is unclear whether Pizzonia will remain in his role as Williams test and reserve driver. He was considered a shoe-in for the second seat at the end of the 2004 season after a string of impressive performances standing in for the injured Ralf Schumacher, but having lost out on a fulltime drive in F1, may choose to look elsewhere to continue his racing career.

Heidfeld, who is believed to carry strong support from Williams' engine partner BMW, was asked to participate in a test for the team at Jerez after it became clear that he was not going to stay with the Jordan team this year. His performance was such that Williams felt compelled to give him the opportunity to prove he was worthy of a race seat.

There followed a lengthy evaluation period between the two drivers over the winter as Williams tried to decide which one should partner Webber in 2005, having lost its case to sign Jenson Button following a hearing with the Contracts Recognition Board.

Heidfeld, who has never raced for a frontrunning team in F1 despite being a protégé of Mercedes through his years in Formula 3 and F3000, has competed in grand prix racing since 2000. Having made his debut with the now defunct Prost team, he switched to Sauber for three seasons, before moving to Jordan for 2004.