Renault form surprises Schumacher

The French squad, with one of the smallest of budgets among the top teams, have won seven of the first nine races of the season as they look more and more likely to retain both their titles.

Fernando Alonso has scored four wins in a row to open a 25-point gap to Schumacher.

The seven-time champion said he was surprised at Renault's pace, and suggested much of it had to do with the tyres.

"In a way yes," said Schumacher when asked if he was surprised by Renault's pace of development ahead of the United States Grand Prix.

"You would think we should have more resources available. But there are two areas: tyre development and car developments, and it depends what area you compare."

Schumacher believes Ferrari have also progressed well, although it hasn't been enough to beat their rivals in recent races.

"There is clearly progress happening," added the German. "If you go back to the races, sort of before England, we looked pretty strong. You see the development we have done and it looked good for us."

Despite his gap to Alonso, Schumacher repeated his intention to keep on fighting until the title is mathematically out of reach.

"We keep on developing, there is nothing more for us to do. We keep on fighting and we will see what happens."