Fernando Alonso said his surprise victory in the Malaysian Grand Prix "changes nothing" about Ferrari's need to improve their car.

The Spaniard leads the world championship after beating Sauber's Sergio Perez in a thrilling rain-hit race.

But he said: "This win will make us very happy but it doesn't change our determination to improve the car.

"We're in a position we don't want - fighting to get to Q3 and take points."

Alonso qualified only ninth fastest in Malaysia as the poor pace of the new F2012 car became just as apparent as it was in the season-opening race in Australia a week ago.

But he and Ferrari took advantage of unpredictable weather to charge into the lead and build a substantial advantage.

Perez came back at him and looked set to take what would have been an even more sensational win but the Mexican made an error, running wide in a corner, and that gave Alonso the breathing space he needed to win.

The victory was the 28th of his career - which moves him ahead of Sir Jackie Stewart in the all-time list and behind only Michael Schumacher, Alain Prost, Ayrton Senna and Nigel Mansell.

"The goal [in these early races] was not to lose too many points to the leaders, and we did the job," Alonso added. "This is a positive move.

"At Ferrari when things go well everything is exaggerated and when things go bad it is dramatic. It is not affecting us.

"Coming to the [next three races in] China, Bahrain and Barcelona, there is a lot of stuff coming to improve the car.

"This is the real job we have to do. We will be working once again in [Ferrari factory] Maranello tomorrow at 8am.

"I remember Korea 2010, there were similar conditions and we grabbed the victory both times, so it seems we like these difficult races. I feel great."