McLaren racing director Eric Boullier believes that Fernando Alonso has not made a mistake by leaving Ferrari for McLaren this season.

The Spaniard spent five years with the Italian team, but opted for a move back to McLaren at the end of last season as he felt that they offered him the best chance of winning a third world championship.

However, McLaren have failed to score a point so far, while Ferrari have improved dramatically and could contend for the championship.

Boullier told Autosport: "I don't think he made the wrong decision. He spent five years there and it didn't work out, and I guess like many sportsmen he looked for a new challenge, if I may say this.

"Coming back here, as he said 'to finish the unfinished business', he knew the project would be difficult to start with because it is very, very young. But he believed in what we said, which was important, he believed in what he saw, which is also important, and he believed in the people and the whole package.

"The drivers know it's going to take time, but they can see the progress at every race, and the way we understand what is happening, what we want to do, how we are building what we want to achieve, and this is very important for them."

Alonso previously drove for McLaren in 2007, but left after falling out with the team.