Feb.27 (GMM) Fernando Alonso has downgraded his chances of winning a third world championship this year to just "30 per cent", but denies that he is being overly pessimistic.

"No, not at all," the former McLaren driver told Spanish radio Cadena SER whilst in Barcelona for the final test before Melbourne.

"To say that we will be between position seven and nine on the grid in Australia is not pessimistic, I just respond honestly to questions.

"The truth is that we simply lack a car to fight for the podium," Alonso, who returned to Renault at the end of a tumultuous 2007 campaign, added.

The Spaniard estimates the per-lap deficit of his R28 single seater to the front runners as about half a second per lap.

"The car is better than it was last year, but we continue to struggle with the Bridgestone tyres," he explained.