Lotus team boss Eric Boullier says the Enstone-based squad is 'cautiously optimistic' about the future after Kimi Raikkonen set the pace on the final day of pre-season testing in Spain.

Raikkonen's time of 1min 22.030secs was the quickest seen over eight days of running at Catalunya over the past two weeks, giving Lotus reason to cheer after it was forced to cancel its running on the first four-day test due to a problem with the new E20.

The revised car was quickest on three of the final four days - with Romain Grosjean quickest on day one and day two - and Boullier admitted that the performance during the final test was a credit to the team for the hard work it had put in.

"After the disappointment of last week, this test was crucial and I think we did a good job," Boullier said. "First of all, we've been able to confirm that the changes made to the car fixed our front suspension problems. We were confident that the redesign was well conceived and well executed, but we have demonstrated the integrity of the modified part. It is a tribute to the all team, which has been working amazingly hard over the last few days in order to fly the E20 on time to Barcelona.

"Despite the rain and a few technical glitches, we managed to learn more about the new car. We now have a better understanding of it, and have a few positive setup directions that we can take further. Moreover, both drivers seem happy with the balance and tyre degradation. We are cautiously optimistic for the future and now looking forward to Melbourne."

After a troubled run in the car on Saturday, Raikkonen was pleased with a problem free final day on Sunday although he played down the fact he had topped the times - arguing that it would count for little when the teams arrive in Melbourne for the opening race of the year.

"I was happy with today's running," he said. "We didn't have any major issues so it was certainly better than yesterday. Everything worked, we tried a lot of set-ups on the car and it all came together well. It was a long time in the car today but I feel fine. It was cooler today so the tyres didn't work as well as otherwise but everything was okay.

"Of course, the fastest time at the end of the day looks good but no-one will know how fast any of the cars are until we get to qualifying at Albert Park. All the changes we have made over testing have been improving the car, so we'll have to see what happens in Melbourne in a couple of weeks' time. I'm feeling positive."