Fernando Alonso says the prospect of Renault not making a step forward in 2008 is a worry for him.

After a one-year absence from the team, the Spaniard spearheaded a seemingly competitive return at Jerez last week, despite the R27 single seater rarely being in contention for podiums in 2007.

"My fear is having a bad year and fighting for eighth position with no motivation," Alonso told the Spanish broadcaster Telecinco.

"It is important to get up and fight for podiums and good results to keep motivated and push forward," he insisted.

Alonso won back-to-back titles with the French team in 2005 and 2006 and has returned to Renault this year after falling out with his employer of 2007, McLaren.

Despite his fears, Alonso said he is confident that Renault will produce a good car for 2008. The R28 will make its track debut this week.

"I think we will have a good car, because the development of the R27 was stopped in June so the full focus can be on the new single seater," Alonso observed.

"In all those months, I believe something good must have been done. We will find out next week, but it will be better than 2007," he said.