Mar.4 (GMM) Despite dominating Champ Cars in recent years, multiple series champion Sebastien Bourdais cannot expect to switch to F1 this year and be immediately at home, his new team boss Franz Tost insists.

Indeed, the 29-year-old Frenchman admitted recently that, although fairly close to the pace of his Toro Rosso teammate Sebastian Vettel in winter testing, his early weakness in 2008 is likely to be the qualifying hour.

"So far Sebastien has done a good job," Tost, the Red Bull sister team's principal, said.

"He has to get used to the rhythm of an F1 race weekend and the first few grands prix will not be so easy for him.

"But I expect he will be a front runner from the fifth or sixth race onwards," the Austrian added.

Bourdais, meanwhile, has expressed relief that he escaped the American series Champ Car before it merged with the Indy Racing League for the 2008 season.

"It's not a merger, it's the death of Champ Car," he said. "I'm even more convinced it (moving to F1) was the right thing for me to do."