Two-time world champion Spaniard Fernando Alonso said farewell to Renault with a solid if disappointing drive to 14th in Sunday's Abu Dhabi Grand Prix - and then expressed confidence in the future he faces at Ferrari.

Despite seeing the two Ferraris, driven by Finn Kimi Raikkonen and Italian Giancarlo Fisichella, finish 12th and 16th in the inaugural day-night race at the Yas Marina circuit, Alonso said he remained bullish about his prospects.

And he explained he felt no concern at joining a team which has struggled all season to run competitively against his former McLaren team.

Alonso, 28, said: "It is not how I wanted to finish my time with Renault but it is not worse or better than we expected. Now I have to think of the future.

"In this season, I think both McLaren and Ferrari started badly. They were at the back - McLaren started even worse than Ferrari but they did a very good job and now they have maybe the best car.

"Here, they were very dominant all weekend and in Brazil also, starting near the back, Hamilton finished on the podium. Really, it is a very quick car.

"But they (McLaren and Ferrari) went with different philosophies. McLaren were pushing with some developments this year and Ferrari did not.

"So, next year, it will be a completely new start for everybody - starting from zero. We have to wait and see which one of the two will have a better car.

"It does not matter too much what you do in the last races. We saw with Renault last year, I finished second in Brazil - and you expect then that Renault would be very strong the following year.

"But we did not get the maximum this year. So every year, every first race of the championship, is a complete unknown for everybody.

"Until the first race next year, we will not know what is going to happen but I am happy that my future team stopped development (of the current car) earlier - because I am sure there will be some benefit.

"Plus Renault stopped earlier. I fully understand their decision and hopefully they can have a good car next year as well."

Meanwhile, BMW bade farewell to F1 with a final flourish, leaving their Swiss-based Sauber team to an uncertain future under new owners.

Germany's Nick Heidfeld finished fifth on the German carmaker's last appearance.

The four points allowed BMW-Sauber to overtake Williams for sixth place in the constructors' standings.

"I'm obviously sad that BMW is leaving but from my side it's nice to leave like this," said Heidfeld, whose own future is yet to be decided.

"It was a very satisfying race for me but in the last couple of laps I had to concentrate because I started to think about it being the last race for the team and everybody. It's quite emotional after four years.

"I hope they (Sauber) will be here next year. I am confident I will be here next year, it's just a question of where," said Heidfeld.

Polish teammate Robert Kubica, who is moving to Renault, finished 10th.

"Thanks a lot to the team for the past four years. I hope to meet them back on the grid next year," he said.

BMW sold the team to Qadbak, a Swiss-based foundation representing unnamed Middle Eastern interests, in September but failed to sign up to the Concorde Agreement governing the sport and have yet to secure a slot on the starting grid which is limited to 13 teams.