Kubica: Renault not podium threat yet

But the Pole is optimistic that upgrades set to arrive for the final test day tomorrow will bring his team closer to the frontrunners.

"We will try to be in the position to fight for the top, but I think it could be difficult to achieve, especially at the beginning of the year," Kubica said.

"We hope for a good start, we hope to be competitive straight away. Of course we have to be realistic, so we will not go to Bahrain to fight for the podium, that's for sure.

"But maybe we will have a nice surprise here on Sunday and then in Bahrain with the new upgrades and we will be able to fight for it."

Kubica explained that Renault had held back on its new aero parts until tomorrow as it wanted to put the strongest possible package on the car when it added the update.

"We were waiting very long because every week there were some new bits that were looking very promising in the windtunnel, so the team decided to wait very long in order to be able to bring to Bahrain as much improvement as we can, and to manufacture something for Barcelona," he said.

"Then we discovered last week that by changing something it would give us an advantage, and I think that's the right approach and there will be no problems in Bahrain.

"It's risky, but I think the team feels quite confident that the correlation between the windtunnel and on the track is very good, so I have no reason to not believe it."

He reckons Renault made a mediocre start to testing, gained ground in the second week of running, and has now perhaps lost a little pace relative to its rivals again.

"I think it was looking very promising in the first test at Jerez, after Valencia where we faced a few problems with set-up, but we reacted very quickly and in Jerez we were looking very strong," said Kubica.

"Then last week we were still okay but I think that we lost a bit of ground. Here it's very difficult to judge because in the end we haven't run much today and it looks like a lot of people have concentrated on quite low fuel runs and then a race distance, so it's quite difficult to understand.

"So we just hope that the new package and new pieces will give us the advantage which we are predicting, and we hope that the other teams don't have many things to put on. Of course they will have - some teams might have already put something on here, maybe some others have not, but we will see in Bahrain in the end."