Leading drivers have refused to be too critical of the problems that threatened to ruin Rockingham's Champ Car debut.

Practice and qualifying had to be cancelled on Thursday and Friday because water was seeping up on to the track in areas called "weepers".

Champs Cars cannot run on ovals when they are wet because of the danger caused by the high speeds.

Race-winner Gil de Ferran said: "This is not an unknown phenomenon.

"It has happened at other tracks in the US, like St Louis, Michigan and Indianapolis. We don't expect it, but it is not unusual."

The big problem at Rockingham was that the track took so long to dry because whenever the surface water was cleared, more replaced it.

Eventually, the race got underway nearly five hours behind schedule on Saturday, after three days of almost completely dry weather.

Kenny Brack, who leads the championship and who finished second in the race, said: "It has happened before, but I don't know that it has taken so long to dry before.

"With these speeds, there is very little time to see a puddle on the track, and if you put a wheel in a puddle at 220mph, it can be disastrous.